# What are your nitrate - guzzling plants?



## Gaina

What are your favorite plants to help control nitrates? I'm having high nitrates at the moment and have ruled out the usual suspects like over feeding, over stocking, filter malfunction, dirty substrate and decaying plant matter (and I'm regular as clockwork with my water changes). 

I definitely need more plants but I want to choose wisely so I get varieties that are fast growing, easy to maintain and good at using up nitrate. 

So far I have:
Bacopa caroliniana 
Echinodorus Bleheri 
Echinodorus Granat 
Sagittaria teres
Cryptocoryne Wendtii Brown
Cryptocoryne petchii 
Microsorium pteropus windelov 
Microsorium pteropus 'Trident' (small but now growing nicely thanks to new food) 
Vallisneria Spiralis 
Amazon frogbit

Would you replace anything or add more of something I already have? 

My tank dimensions are 80 x 35 x 50cm 
Ph 6.6
Temperature 25.5c
Gh 6

Thank you!


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## Konsa

Hi
Why are U concerned about high nitrates.What values U have in the tank.Are U adding any?
Any floater will mop them Nitrates up as not CO2 limited.Just need to make sure U are not missing any other nutrients or U will limit the N uptake of the plant.
Regards Konsa


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## Saffa

I’ve had water lettuce and frogbit a while ago in one of my 350 litre cichlid tanks and nitrates were noticeably lower than other tanks before weekly water changes up to 10ppm lower than same size tank with same/ similar stocking levels


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## Gaina

Konsa said:


> Hi
> Why are U concerned about high nitrates.What values U have in the tank.Are U adding any?
> Any floater will mop them Nitrates up as not CO2 limited.Just need to make sure U are not missing any other nutrients or U will limit the N uptake of the plant.
> Regards Konsa




Hi 

I'm concerned about the long term affects it will have on my fish. Its 40ppm up from 20+ (the usual colour is probably closest to 25).   I'm not running Co2 and my ammonia and nitrite are zero.  I am having a problem with algae on the glass but this tank has only been running about 8 weeks (I ran a mature filter for 3 weeks alongside the new one before adding Livestock back in), so I thought it was just the tank settling in until I noticed the jump in nitrate.



Saffa said:


> I’ve had water lettuce and frogbit a while ago in one of my 350 litre cichlid tanks and nitrates were noticeably lower than other tanks before weekly water changes up to 10ppm lower than same size tank with same/ similar stocking levels



I did notice that the amazon frogbit did make a difference to nitrates in my previous 65 liter tank so I'll definitely be adding a lot more of that. 

The food I'm using is The Aquascaper Complete Food.


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## sciencefiction

If you're not running CO2, the bets plants are those that have access to aerial CO2, such as floaters or emersed plants. You can do as simple as sticking the roots of some pothos plants inside and let it grow outside the tank. Or you can get more complicated on emersed set ups. I have two large mature plants over my emersed pond, a peace lily and a parlour palm. The only limitation is the size of the tank.


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## Konsa

Hi
The Aquascaper complete plant food will contain some nitrates but how much I am not aware as too costly for my budget.
I am heavy doser myself from1/2 to 3/4 of EI values daily  in 3 of my low tech tanks and never bothered with testing the water in my tanks.I am firm supporter of big 50-80% weekly waterchanges and all my critters seem happy chappies.
There are many opinions about Nitrates some believe that they cause long term dammage in ranges over 40-60ppm but for those to become toxic they need to be way higher.On the other hand the high NO3 may be a smoking gun of a previous Ammonia  (Nitrite) spike that went unnoticed trough nitrification  wich  is highly toxic to fish  and thats why ones fish health is in decline .
Plus there is always the doubt of inaccurate hobby grade test kits.
Just keep up your maintenance regular as U do,add more plants and enjoy your tank.
Regards Konsa


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## tam

If it's creeping up slowly then it might just be you need to do a slightly bigger water change or now and then a bonus one mid-week. 

As said, floating plants suck it up best. Any emersed plants too - some people add pothos to suck them up. You have to watch it doesn't go too far and starve your other plants though.


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## BubblingUnder

Put houseplants down the back of your tank like I have (Belt & Braces approach) currently I have: Peace Lily, Pothos, Flamingo Plant, Baby Tears like so....




 

Water change needs are minimal despite having a heavily stocked planted tank. I also rate Frogbit & Java Fern to use the nitrates as well.


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## ian_m

Fish won't suffer nitrate issues until inorganic supplied nitrate (tap water and ferts) is in the order of 1000's ppm. I accidentally ran 350ppm NO3 and 80ppm PO4 after a timer failure on my doser. No change to fish behaviour, no change to plants either. Only noticed a week later when could hear whirring of the pump after dumping 2litres of double strength EI solution into my tank...


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## Smells Fishy

I imagine fast growing stem plants would guzzle nitrates quicker vs something like Anubias. You can't go wrong with using certain house plants, my favorite is my lucky bamboo.


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## Gaina

sciencefiction said:


> If you're not running CO2, the bets plants are those that have access to aerial CO2, such as floaters or emersed plants. You can do as simple as sticking the roots of some pothos plants inside and let it grow outside the tank. Or you can get more complicated on emersed set ups. I have two large mature plants over my emersed pond, a peace lily and a parlour palm. The only limitation is the size of the tank.



I'm fascinated by pothos, actually as a lot of fish keepers I subscribe to on YouTube love it.  Unfortunately I have a lidded tank which needs to be that way to combat condensation in my room (I noticed it's reduced significantly since getting my new tank).  I think having read everyone's thoughts I'm going to opt for more frogbit. 



tam said:


> If it's creeping up slowly then it might just be you need to do a slightly bigger water change or now and then a bonus one mid-week.



I think what may have happened is I was unable to do my fairly large water change when  my whole family, myself included went down with flu, but I managed a smaller one, so maybe it started there. I'm back on normal schedule now so I can do any necessary additional water changes quite easily.



ian_m said:


> Fish won't suffer nitrate issues until inorganic supplied nitrate (tap water and ferts) is in the order of 1000's ppm. I accidentally ran 350ppm NO3 and 80ppm PO4 after a timer failure on my doser. No change to fish behaviour, no change to plants either. Only noticed a week later when could hear whirring of the pump after dumping 2litres of double strength EI solution into my tank...



That's very reassuring, thank you.  I am very conscious that panicking and taking drastic action would probably do more harm than good so I'm more sure of what I need to do next, thank you.


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## HiNtZ

Why are you worried about nitrate if you have plants? The levels would never get anywhere near enough to upset the fish. I've been adding 35ppm NO3 & 8ppm PO4 per week for years and my fish and shrimp are happy, vibrant colours, spawning even.

The only two worth checking are nitrite and ammonia, but on an established system even this is a bit pointless unless your fish are showing signs of discomfort.

My advice would be to ensure that you have the full spectrum of nutrients present in the water column - K, P, Fe, Mg etc just so there are no uptake issues and nothing gets locked out due to a deficiency & keep on with your water changes as usual.

Search the forums for posts discussing test kits and their terrible reliability, especially in dosed tanks - something to do with organic (or inorganic, can't remember) forms of N giving false readings. The way I understood that discussion is although the test kit shows N, it might not be in a form that is available to the plants so readily. Due to my lack of understanding on this issue, I simply just dose a set amount of fertiliser per week and leave the test kits well alone (unless testing my RO).

As for fast growing plants, my limnophila sessiliflora grows 4 inches a day, yes that is PER DAY. It also will put on 2 inches over night. Now if that's not sucking nitrates, I'd be very surprised.


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## dw1305

Hi all,





HiNtZ said:


> As for fast growing plants, my limnophila sessiliflora grows 4 inches a day, yes that is PER DAY. It also will put on 2 inches over night. Now if that's not sucking nitrates, I'd be very surprised.


That is pretty much it.

An actively growing plant is depleting nutrients from the water column. If you have plenty of PAR, <"abundant CO2"> and non-limiting mineral  nutrients you can have exponential growth. This is from <"Phytoremediation to remove nutrients from eutrophic storm water using _Pistia stratiotes"_>. 





> Inorganic N (NH(4) (+) and NO(3) (-)) concentrations in treatment plots were more than 50% lower than those in control plots (without plant). Reductions in both PO(4) (3-) and total P were approximately 14-31%, as compared to the control plots. Water lettuce contained average N and P concentrations of 17 and 3.0 g kg(-1), respectively, and removed 190-329 kg N ha(-1) and 25-34 kg P ha(-1) annually.


 Plants from <"varzea lakes and "floating meadows""> along the white water rivers of the Amazon basin have <"huge potential growth rates">, because they live in a world where everything is turned up to 11, every day.

This is <"_Victoria amazonica_ at RBG KEW"> (in the Water lily house).





and this is what Kew say about light and nutrients 





> .........Carlos Magdalena, who cultivates this species at Kew, notes that temperature and light are crucial. The seedlings are raised at 32 °C and the juvenile and adult plants are grown on at 26 to 32 °C. In the winter, supplementary lighting must be provided for the seedlings. A 400 watt horticultural supplementary bulb is used to give bright light for 12 hours. The brighter and longer the exposure to light, the better and faster the plant grows. Eventually, in autumn, it is the lack of light that finally causes the plant to die.......The general rule is: the larger the pot, the larger and healthier the plant. General maintenance includes weekly feeding throughout the season using 'feed bombs' and prompt removal of decaying leaves......


cheers Darrel


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## alto

Go back a few years & the internet abounds with _nitrate shock_, _nitrate toxicity_ posts & articles

Somehow this has transformed into a seeming collective _nitrate is benign_ regardless of concentrations or sudden elevations 

I'm sort of a Science person 
while there are some species that appear resistant to even very high levels of nitrates ie no apparent effect observed on behaviour or growth, eg, channel catfish - I'm not much interested in keeping channel catfish in my aquaria so while I've read several articles I'm not inclined to dig out the links (that few seem interested in reading anyway  ) -
I suspect that the ornamental fish I do keep in my aquarium share more properties with zebrafish

*Nitrate and nitrite exposure affect cognitive behavior and oxygen consumption during exercise in zebrafish*

Zebrafish have been avid science contributors for decades 
(I'd be surprised if the human nitrate guidelines didn't begin with zebrafish experiments) 




Gaina said:


> I'm concerned about the long term affects it will have on my fish. Its 40ppm up from 20+ (the usual colour is probably closest to 25).


There are significant papers confirming biochemical effects of nitrate exposure to support your concern 

*Nitrate toxicity to aquatic animals: a review with new data for freshwater invertebrates*

You don't mention how you're measuring nitrates or which water conditioner you're using, I'd suggest a Seachem test kit which includes a nitrate reference standard as this should help clarify what's happening with your aquarium & test measurements (you may find other similar kits locally, look for salicylate based nitrogen kit (rather than nessler)

It's impossible for nitrate to generate spontaneously  so you should be able to sort out where the unexpected readings are coming from


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## AverageWhiteBloke

Surely the simple answer to reduce nitrates would be just to dose some traces like tropica and Epsom salts for a while? The other ferts contain nitrates so essentially you are adding them then looking for ways to get them back out. Maybe just dose the Aquascaper Complete Food when plants look a bit washed out.


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## dw1305

Hi all, 





AverageWhiteBloke said:


> Surely the simple answer to reduce nitrates would be just to dose some traces like tropica and Epsom salts for a while? The other ferts contain nitrates so essentially you are adding them then looking for ways to get them back out. Maybe just dose the Aquascaper Complete Food when plants look a bit washed out.


That would be my suggestion as well. I like plants as my visual indicators of nutrient content, simply put the plants don't lie.





alto said:


> I suspect that the ornamental fish I do keep in my aquarium share more properties with zebrafish


 and I suspect that you are right.

There is discussion of this in <"A simple continuous .....">, and links. I think the most relevant data is probably from Salmonid aquaculture, because they are fish that have very high water quality requirements, higher than even rheophilic tropical fish.

In the <"Technical report: Salmonids in recirculating aquarium systems..."> it talks about nitrate parameters being different between high flow and low flow systems, and not being an issue in high flow systems (I assume this is due to higher levels of dissolved oxygen, but I don't know why), the upper limit given is 10 ppm NO3, and the reference is <"Molleda, M.I., 2007. Water Quality in Recirculating Aquaculture Systems for Arctic charr (Salvelinus alpinus L.) Culture, Project report - Fisheries Training Programme. The United Nations University">, I've just got a copy but I haven't read it yet.

Aquaculture papers are quite interesting because they look at (sub-lethal) parameters that effect fish growth rate. Toxicology papers tend to look at LC50 values.  

The Zebra(fish) Danio (_Danio rerio_) paper use NaNO2 and NaNO3 as its source of NO2-/NO3- ions. If you convert the 606 mg/L (ppm) NaNO3 to ppm NO3- you get 442 ppm NO3- (RMM 85 and 62/85 ~ 73% NO3), so we are still talking pretty elevated levels of NO3-.

cheers Darrel


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## zozo

dw1305 said:


> nitrate parameters being different between high flow and low flow systems, and not being an issue in high flow systems (I assume this is due to higher levels of dissolved oxygen, but I don't know why),



Always thought that in high flow system there is little accumulation of sediment.. All high flow streams in my area all have slipery rocky/stone substrates with some accumulating in the lee of bends and dams. While low flow or stagnant always is a massive accumulation of decompossing muddy sludge. I have an old artifical lake behind my house, i used to go fishing and sometimes swimming there. about 1/3 of it was rather shallow and i could walk all away across a few 100 meters from hip to chest deep but in about 40cm deep soft and slimy sludge. Never realy experienced this crossing anything that flows.


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## AverageWhiteBloke

Just for record should probably mention for the OP, I meant Tropica Premium not Specialised. Specialised also contains nitrogen. 

Sent from my STH100-2 using Tapatalk


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## AverageWhiteBloke

zozo said:


> Never realy experienced this crossing anything that flows.



I guess the finer sedimnent gets washed away in these systems Zozo just leaving the heavier rocks behind.


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## zozo

AverageWhiteBloke said:


> I guess the finer sedimnent gets washed away in these systems Zozo just leaving the heavier rocks behind.



Yes that's what i mean.. And thought obviously less decomposing mater to encreas Nitrate parameters and such.. All is kinda washed out and ends up in the lee patches or pushed against the shore sides where marginal growth thrives on it. That's what i assume in my imagination, just a theory i do not know if that's realy the case why next to the higher oxygenation the nitrate levels alledgedly are lower in streaming waters.

Way back about 25 years maybe when i still did fishing and  a club board member with the task, "Water and Flora mannagment" i monthly needed to put on my wadding suit and take water samples from the lake and bring the samples to the local wildlife inspector. So nothing highly educative  nor didn't made desicions on my own i was the local wildlife inspectors right hand muscle to get him the samples and do the diggin or log and report observations.. And he was the brains and did send it on to te lab etc.. I was instructed to always take water samples from 1 metre depht. Closer to the surface and any deeper was no good to get an good average result. Likely to do with temperatur, surface movement and water oxygenation.


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## AverageWhiteBloke

zozo said:


> All is kinda washed out and ends up in the lee patches or pushed against the shore sides where marginal growth thrives on it. That's what i assume in my imagination,



Sounds about right that mate. From what I understand that's how it works in the oceans. People think that all the oxygen produced by the Amazon rain forest comes from the plants and trees that grow there but I think it mainly comes from the nutrients washed out the rivers into the ocean which then feeds the plankton and algae.


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## sciencefiction

zozo said:


> Always thought that in high flow system there is little accumulation of sediment.. All high flow streams in my area all have slipery rocky/stone substrates with some accumulating in the lee of bends and dams. While low flow or stagnant always is a massive accumulation of decompossing muddy sludge. I have an old artifical lake behind my house, i used to go fishing and sometimes swimming there. about 1/3 of it was rather shallow and i could walk all away across a few 100 meters from hip to chest deep but in about 40cm deep soft and slimy sludge. Never realy experienced this crossing anything that flows.



I think in the article Darrel posted they're talking about RAS systems with high flow through the filter vs low flow rate through the filter, which is obviously an impacting factor on efficiency of ammonia and nitrite conversion but can also be a factor of oxygen delivery to the filter media. There is no sediment to speak of, it is mechanically removed. Dissolved organic compounds are also mechanically removed and dissolved oxygen levels in the water column are continuously monitored, etc. etc... So the issue I think is not accumulation of organics, the issue is, as Darrel suggested, oxygen delivered to the filter. Or at least that's my theory.  Low flow through the filter - low oxygen to the filter.....

_Nitrate, the byproduct of the conversion of NH3 and NO2 within the system biofilter (nitrification) is not an issue in high flow systems, however, in those with low water flow rates it has become an increasingly important parameter and concentrations no higher than 10 mg L-1 should be maintained (Molleda, 2007)._

In response to the above quote from the same study, I think the nitrate toxicity issue in high vs low flow systems is oxygen levels in the filters. Low flow and low oxygen conditions would produce a partially anaerobic filter, thus denitrification in the filter would occur. When nitrate levels are high/elevated,  nitrate to nitrite conversion will occur and the actual toxicity observed from high nitrAtes is actually from spiking nitrItes.

See below study and the quotes I took from it....It is basically testing prolonged nitrate toxicity on fish by the addition of 200ppm nitrate in different forms, such as sodium nitrate and potassium nitrate. They do observe mortality at those levels after several weeks but they do notice increased nitrite levels, hence how can one say a fish died because of 200ppm nitrate when there is nitrite in the water.......


_"Fish exposed to the sodium nitrate and potassium nitrate began to die after six weeks at the elevated nitrate levels (200ppm)_

_With the exception of nitrate concentrations purposefully outside these ranges, *our water quality was within the proposed
ranges for all water quality parameters except for nitrite*. When nitrate levels were elevated due to
addition of a nitrate salt or from nitrification, increased nitrite levels were observed. This increase
in nitrite was most likely due to enhanced reduction of nitrate to nitrite caused by the elevated nitrate concentrations"_

_Nitrate Toxicity: A Potential Problem of... (PDF Download Available)_. Available from: https://www.researchgate.net/public..._A_Potential_Problem_of_Recirculating_Systems [accessed Apr 11 2018].

So my point is, are we sure that the health problems associated with high nitrates are not actually random/chronic nitrite spikes that can occur in tanks with favorable conditions for denitrification? There are actually fish keepers that try to promote denitrification in order to reduce nitrates.....How dangerous is that?


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## zozo

sciencefiction said:


> I think in the article Darrel posted they're talking about RAS systems with high flow through the filter



Yes indeed, sorry i red that wrongly and thought it was about high flow natural waters. Thanks..


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## sciencefiction

zozo said:


> Yes indeed, sorry i red that wrongly and thought it was about high flow natural waters. Thanks..



Me too the first time


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## zozo

Dont worry.. It's a lot to take in..  Or out.. For us hobbyists... Depends..


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## sciencefiction

sciencefiction said:


> So my point is, are we sure that the health problems associated with high nitrates are not actually random/chronic nitrite spikes that can occur in tanks with favorable conditions for denitrification?



To add to the above, Diana Walstad pointed out the exact same thing in her book I read some years back. She claimed that there is no study that she had read at the time that proves nitrates are toxic and the only studies that measured negative effect of elevated nitrates, also reported elevated nitrite levels....I personally would ignore studies that don't report nitrite levels when testing nitrate toxicity because those two parameters are too closely related and the study would be biased or incomplete, and the conclusions on toxicity, toxicity levels, etc.... reported could be wildly wrong.

For example in the study Darrel posted as per the below, quote, their figure of 10 mg L-1 nitrate is not backed up by anything else, bar mentioning that in high flow systems the issue isn't the same...One thing is for sure.,nitrate can't be toxic and non-toxic at the same level, at the same time in the same system, with the same exact fish, unless it is not the nitrate toxicity at play, but something else....i.e. nitrite..



dw1305 said:


> Technical report: Salmonids in recirculating aquarium systems..."


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## sciencefiction

alto said:


> There are significant papers confirming biochemical effects of nitrate exposure to support your concern
> 
> *Nitrate toxicity to aquatic animals: a review with new data for freshwater invertebrates*



This paper for example is just stating numbers.....I don't have information to doubt them but I am also not given any information I can use to verify their conclusions. Hence, it is sort of useless to me personally... What type of nitrate did they dose, what other conditions were the critters kept in, any other parameters recorded, etc..?



alto said:


> *Nitrate and nitrite exposure affect cognitive behavior and oxygen consumption during exercise in zebrafish*
> 
> Zebrafish have been avid science contributors for decades



As per the study, they were exposed to either sodium nitrate (606.9 mg/L), sodium nitrite (19.5 mg/L), The nitrate level seems rather high.....Plus, how much sodium is there in 606.9 mg/L sodium nitrate I wonder? How about the effect of sodium on fish? I won't even bother reading the nitrite portion...not relevant as we try keeping nitrites in fish tanks at zero...


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## sciencefiction

There's one more random study on nitrAte toxicity I clicked on...


*Comparing the effects of high vs. low nitrate on the health, performance, and welfare of juvenile rainbow trout Oncorhynchus mykiss within water recirculating aquaculture systems*
https://www.sciencedirect.com/science/article/pii/S0144860914000041#tbl0020


After reporting all the "toxicity" levels and effect of nitrate in their two study groups, they also say the following somewhere down the bottom....

_Several other water quality parameters were significantly different between treatments. These parameters included *nitrite* nitrogen......*Nitrite nitrogen*, total suspended solids, boron, and potassium concentrations were *significantly greater* within the high NO3-N treatment._

So again, they observed elevated Nitrite(NO2) in the high Nitrate(NO3) fish tank....so were they observing high nitrate toxicity effect or elevated nitrite toxicity effect on fish? Who knows.....


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## tam

The way I see it is there is no benefit to the plants to having more nitrate than they need. The science is still unclear on long term/subtler effects of nitrate on livestock. So the goal of keeping nitrates around the point that is plenty for what the plants need but not significantly higher (and increasing) seems a good compromise. Keeping at that point might be adjusting your dosing, water changes, fish and/or plant load - whatever works for you and your tank.

I also think that if you goal for your tank is to use plants to keep the nitrates as low as possible for the fish, that's just as valid as using them to create a miniture underwater landscape.


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## sciencefiction

If high nitrate levels(NO3) have an indirect effect, via denitrification, elevating the nitrite(NO2) in the system, then it is perhaps wise to keep nitrate levels low. I think that the reason higher nitrate levels are not a problem in a heavily planted tank is because the plants themselves use all forms of nitrogen, be it in ammonia, nitrite or nitrate form. Plus a well maintained high tech planted tank, besides fast growing plants,  would have rather high flow through the filters, would also be water changed quite regularly and filters would be kept clean to prevent algae. So the possibility of denitrification is minimized, hence high nitrates aren't backfiring. From the studies it seems that the "effect of nitrates" , i.e nitrites perhaps,  isn't instant but cumulative, meaning it happens after a certain time of exposure. RAS systems for example, which are pretty similar to a bare fish tank which isn't water changed very regularly, have only the filter as a back up and no other means of reducing nitrite levels(NO2), plus water changes are minimized. So when denitrification occurs only partially and thus produces nitrites, there isn't any back up and it would directly affect fish. That's my view of it anyway.

Personally I avoid anything that can cause denitrification or anaerobic conditions in my set ups.  My substrate is always just bare minimum. One of my more heavily planted tanks barely has 2 cm substrate and I can uncover the roots of the crypts just by brushing off a few mm of sand. My emersed plant set up only has a few mm of sand as substrate. I keep sponges as pre-filters to keep my main filters clean. I try to have high oxygen levels and I have high flow in all set ups in the means of high flow/oversized filters. I do large water changes and I am reluctant to dose nitrates unless I see it necessary. I may not dose for months or a year. I just don't see the point in it because I use the plants to reduce the nutrient/mineral level, not to maintain or increase it. I'd rather have sub-optimal plant growth than sub-optimal fish health, providing there is indeed a risk, and there obviously is.....It may not happen in each tank but it can happen. For the same reason I don't inject CO2. Additionally, I keep my TDS readings to base readings of tap water to avoid accumulation of anything else I am not capable of measuring via other means. I don't have aesthetically pleasing setups but I know how to keep fish healthy and long living providing some of the hardware doesn't fail on me, or the tanks cracking open as that has happened....And of course, overstocking will always kill fish one way or another...


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## dw1305

Hi all,





sciencefiction said:


> As per the study, they were exposed to either sodium nitrate (606.9 mg/L), sodium nitrite (19.5 mg/L), The nitrate level seems rather high.....Plus, how much sodium is there in 606.9 mg/L sodium nitrate I wonder?


You can work out the sodium level, it is 23/85, so ~ 35% of 607, about 200ppm.





sciencefiction said:


> I think the nitrate toxicity issue in high vs low flow systems is oxygen levels in the filters


I assume it is, faster flow would give you system with more dissolved oxygen, via a larger gas exchange surface.


sciencefiction said:


> So my point is, are we sure that the health problems associated with high nitrates are not actually random/chronic nitrite spikes that can occur in tanks with favorable conditions for denitrification? There are actually fish keepers that try to promote denitrification in order to reduce nitrates.....How dangerous is that?


I'm not sure there is any work that quantifies the nitrite production from the anaerobic conversion of NO3- to N2 gas, you are back to what happens in the zones of fluctuating REDOX in the filter & substrate etc. and that wouldn't be easy to quantify or model.

I also think we are back into ecological "diversity brings stability", because more than one type of bacteria are involved and <"more than one enzymatic pathway has been identified">.





tam said:


> I also think that if you goal for your tank is to use plants to keep the nitrates as low as possible for the fish





sciencefiction said:


> I just don't see the point in it because I use the plants to reduce the nutrient/mineral level, not to maintain or increase it. I'd rather have sub-optimal plant growth......


This is the really important bit, if you have a large plant mass the plants are going to mop up all forms of fixed nitrogen, it doesn't really matter where nitrification (or denitrification) is occurring, the plants will respond to more nitrogen with increased growth.

If you want plants that grow really quickly (or want to grow plants that need everything tuned up to 11) then you can add plenty of nutrients. It is the "Tomato growing approach" from <"Does excess P.....">. 

Personally I just want some active plant growth, and <"ideally the slower the better">.

cheers Darrel


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## dw1305

Hi all,





dw1305 said:


> You can work out the sodium level, it is 23/85, so ~ 35% of 607, about 200ppm.


Sorry some problems with basic mental maths there, and 23/85 is less than 1/3 and nearer 1/4, so that should be about 160ppm Na.

cheers Darrel


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## AverageWhiteBloke

Just my penny's worth and observation, I haven't got much to support this. I feel like EI or Eutrophic dosing does serve a purpose however I would suggest in the vast majority of tanks it isn't necessary. I've tried a different approach to keeping my tanks of late which seems to yield better results in the long run. I notice a lot of people in the forum tend to go kitchen sink right from the off and the pattern seems to be with 4 to 6 weeks they hit problems. The tanks I've been doing I started with everything bare minimum in so far as lighting and dosing, initially just traces and magnesium. I find there are very few plants if any that can't deal with this. Very gradually over time and using a TDS pen to gauge the direction of the tank combined with plant health observation I will increase the lighting. If the trend on the tank is for the tds to keep lowering and I see a negative reaction in any of the plants I dose a very small amount of npk weekly and wait to see if things stabilise, rinse and repeat until my lights are at 100% for the time I fancy generally between 7/8 hrs. What I do find that these setups need nowhere near EI levels of dosing which I have dosed EI before on the exact same setup and had numerous issues. 

As far as co2 goes, I find that I will hit a point when increasing ferts and lighting will result in a co2 related issue in which case I add a small amount which seems to balance out the tank again rather than chasing 1 point drops and yellow DC's. I also find that I can get a little shortage of ferts without a disaster as long as the tank is kept clean. Running this way on a more granular level and feeding on a as needed basis rather than a too much of everything philosophy seems to be less problematic but I'm just a hobbyist who likes to see some fish knocking about in some plants and like @sciencefiction I don't think you'll see any of my tanks in any aquascaping competitions any time soon. 

I just think it's better to run things with what it needs but it takes a bit of experience. If we have lots of everything in there it's hard to put your finger on what might be causing an issue. So many elements, so many possible reactions and us mere mortals don't really know how they all react when combined. Fair enough they're all known to be safe with fish when exposed to them but as for what happens when they are mixed together is anybody's guess.

My understanding is that given the chance a plant will solely use ammonia as a source of food against nitrate so in the initial setup period when I would imagine ammonia is about in abundance is there any need to be dosing nitrate? Once this cycle is over we start producing nitrate and then the fish go in and nitrate builds up further. I don't we need to add much more in a decent stocked tank. I would imagine nitrite would be the worst offender and definitely the likes of heavy metals like copper would be in the running when dosing Eutrophic. From what I gather nitrite is more toxic in acidic conditions which most tanks are run at by injecting whereas ammonia is "safer" in acidic conditions. People who does EI tend to keep their tanks scrupulously clean so little DOC to bind up metals although I guess most of them in the traces are already bound to the chelators, don't know.

Begs the question, I wonder if plants get lazy. They've built up reserves and are feasting in a nutritious soup of nitrogen and at only takes a little bit of anaerobic activity in the filter, a dead fish or bit of food to generate just enough nitrite that sits in the tank for just that little bit too long in acidic conditions to top a fish. A couple of hours later everything is fine but people get a false positive nitrate reading and the myth continues. Perhaps that little nitrite spike would have been mopped up a lot quicker by the plants if they were a little hungrier. 

There's always more questions than answers in the game although I'm sure Clive will pop up any minute now and answer all those with something else I don't understand


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## roadmaster

I think in 4 to 6 week window (any tank),plants are still adapting under often times high light energy(too much maybe?), and low or poor CO2 environment, and possibly low nutrients.(fearful of nutrient's = algae).
Tanks don't mature for month's IMHO
I would want to hedge my bets with lower lighting in the beginning,and ample to excess nutrient's to draw from rather than limitation,or minimum whatever that is, while getting the most I could from CO2 application.
Does anyone really believe that the 20 or 30 ppm CO2 we might inject, and often heralded, compares to the 300 ppm that many of the same plants we attempt to grow submerged see  in the wild?
It seems to me, that beginning a tank with limitation's on anything but light energy,is recipe for problems/failure.
Trying to provide only the nutrient's that plant's might need over EI dosing for example,  is to me pointless, for the plant mass is always increasing (we hope) and more plant mass = more food's needed no?


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## AverageWhiteBloke

roadmaster said:


> Trying to provide only the nutrient's that plant's might need over EI dosing for example, is to me pointless, for the plant mass is always increasing (we hope) and more plant mass = more food's needed no?



I think that's sort of what I'm saying, I don't limit as such more if I'm adding "some" and there appears to be no issues I just don't see the need to be adding anymore. i don't think they are limited more getting what they want and no more. Obviously as plant growth increases they will want more which generally indicated by TDS dropping and the floating plants which seem to succumb first and then I adjust accordingly. I could say the hell with it and pile EI in and be done I guess. I was just pointing out that I've seen tanks with 1 drops of PH and EI got tits up quite quickly, indeed tanks I have setup have done the same on this path. The same spec tanks I have setup this way were less problematic in so far as I let the tank tell me what it wanted rather than me telling it what it was getting. What I did realise was that with a similar amount of plant biomass and the same lighting/duration and brightness that tanks I had previously dosed religiously and keeping the DC the right colour could quite easily have been ran with just some co2 enough to make the DC change from blue to a dark green and with about a quarter of EI dosing. 

Obviously just my own personal experience and I can't validate it with any science I'm afraid but it worked for me. Maybe I'm just getting better at growing plants


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## AverageWhiteBloke

I'm outa here, just noticed Clive's logged in. It's all yours


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## roadmaster

Light energy, just enough and no more, is what helped me turn the corner.
Could easily realize less CO2 or nutrient's needed than might be needed with 50 or 100 PAR at the substrate that many fixate on.
Nobody talks about limiting light energy, but will jump through hoops for a long long while to get the problem free tank and prospering plant's they wish for, while maybe reduction in light was all that is/was needed all along.
Maybe so, they were or are just on the cusp of having such a beautiful problem free tank, but they won't move off the uber high $$ lighting.(stubborn)
Have spoke to those who confessed that reducing the light energy/duration was what finally brought them desired result's not just in low light affair's, but full on high energy gas injected.
Some were embarrassed to say how long they battled before they came to their own conclusion about the light which drives everything.
Have also noted that some of the most handsome tanks I have seen have lighting hung high above the tank where better light spread along with less PAR would be the result.


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## ceg4048

alto said:


> Go back a few years & the internet abounds with _nitrate shock_, _nitrate toxicity_ posts & articles
> 
> Somehow this has transformed into a seeming collective _nitrate is benign_ regardless of concentrations or sudden elevations
> 
> I'm sort of a Science person


And therefore, the conclusion, evidently, is that a few years ago, the information on the internet, abounding with _nitrate shock_, _nitrate toxicity_ posts & articles must have been true, while the latest information reporting benign nitrate must be false.

It seems odd that a Science persons, typically known for their attention to detail, would interpret the transformation as "..._nitrate is benign_ regardless of concentrations or sudden elevations..."
I don't recall our ever stating that or ever reading any articles to that effect. What we have stated and have seen clearly delineated in the articles is that the level of NO3 that we dose in our eutrophic dosing schemes doesn't come anywhere near the reported toxic levels reported in the articles. In fact the dosing schemes provide NO3 levels at several orders of magnitude below the toxic levels stated in the articles -even when added to the resident NO3 levels in tap, we are still far below any acutes or chronic toxic levels.




alto said:


> ...while there are some species that appear resistant to even very high levels of nitrates ie no apparent effect observed on behaviour or growth, eg, channel catfish - I'm not much interested in keeping channel catfish in my aquaria so while I've read several articles I'm not inclined to dig out the links (that few seem interested in reading anyway  ) -
> I suspect that the ornamental fish I do keep in my aquarium share more properties with zebrafish
> 
> *Nitrate and nitrite exposure affect cognitive behavior and oxygen consumption during exercise in zebrafish*
> 
> Zebrafish have been avid science contributors for decades
> (I'd be surprised if the human nitrate guidelines didn't begin with zebrafish experiments)


Again, as mentioned by other posters, 607 ppm NaNO3 yields a nitrate concentration of over 440 ppm - that is 10X the highest level of NO3 in European tap and over 20X the EI dosing level.




alto said:


> .There are significant papers confirming biochemical effects of nitrate exposure to support your concern





alto said:


> *Nitrate toxicity to aquatic animals: a review with new data for freshwater invertebrates*


Yes, I'm sure there are enough papers that if interpreted properly, will support whatever confirmation bias is necessary to support all kinds of fears.
Lets extract some data from this paper:


> Meade and Watts (1995) examined the toxic effects of NaNO3 on the survival and metabolic rate (oxygen consumption) in juvenile individuals (9–13 mm total length) of the Australian freshwater crayfish _Cherax quadricarinatus_. After 5 days, no mortality was observed in crayfish exposed to a nominal nitrate concentration of 1000 mg NO3-N/l. Furthermore, no significant difference was observed in oxygen consumption between control (0 mg NO3-N/l) and experimental (1000 mg NO3-N/l) individuals [this yields a Nitrate concentration of 4300 ppm].





> Rubin and Elmaraghy (1977), after examining the acute toxicity of KNO3 to guppy (_Poecilia reticulatus_) fry, calculated 24, 48, 72 and 96 h LC50 values of 267, 219, 199 and 191 mg NO3-N/l


This last example should be illustrative of what we have been stating repeatedly. In order to kill 50% of a sample of guppy *fry *it required in this experiment: 1150 ppm NO3 (24 hours), 940 ppm (48 hours),  855 ppm (72 hours) and 821 ppm (96 hours).

Now, if Science persons are too lazy to look at these numbers and to compare them to the numbers in the dosing schemes then they will not be able to reconcile our statements regarding the benign nature of NO3 dosing.

If folks want to maintain their fear of NO3, which is actually natures way of detoxifying the environment against the highly toxic NH3 and NO2, then there is nothing that can be said to change their opinion. In fact, my contention is that the OP is not even asking the right question. What he should be asking is what plants are the most NH3/NH4 guzzling.

I reiterate that being paranoid about NO3 leads the hobbyist into making the wrong decisions and turning him/her away from potentially problem solving paths.

Cheers,


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## AverageWhiteBloke

Dodged that bullet  Nitrate isn't a concern of mine for the above points, we are never going to get anywhere near "toxic" levels whatever they may be interpreted by whatever test that hasn't took other parameters into consideration. However there's a few points been raised in the fork the original post took which interest me. In a eutrophic dosing system is the ability for a nitrite spike increased with the excess of nitrate should say the filter become anaerobic for a short period, I'm also thinking about in cases where substrate has been piled up in the back like scapers do to create a sense of perspective. Some times you see these scapes where the soil at the back can be 5 to 6 inches thick, I would guess creating a breeding ground for anaerobic activity.

Also do plants get lazy in so far as soaking up nitrite when there is an abundance of nitrogen available to it and they are well fed. I suppose common sense would tell you that healthy plants fed well would quickly neutralise any nitrite that managed to creep in but if they have ate their fill if you like would nitrite sit for longer than necessary or would the filter itself mop it up pretty quickly obviously as long as it wasn't the filter itself that caused the spike in the first place.

I guess I'm just wondering if nitrate could be getting the blame of a nitrite spike which then sneaks off into the background when o2 levels increase. I guess the optimum time for nitrite to strike would be in a perfect storm of clogged filter, deep substrate and through the night when o2 is at its lowest in acidic water and the plants aren't feeding. Maybe why people wake up to a dead fish. They never seem to go through the lit period or that could just be me.



roadmaster said:


> Maybe so, they were or are just on the cusp of having such a beautiful problem free tank, but they won't move off the uber high $$ lighting.(stubborn)



Hence my avatar mate  The thing is with my tanks, I think I seriously over estimated the amount of light they were putting out. Looked bright to me sitting in the house at night but I have no way of measuring it. Previously I just dosed EI indiscriminately, this was causing a TDS rise above and beyond what I was expecting to see taking normal waste rise into account. Next time I was setting up I had a pair of German Blue Rams to cater for which I had one eye on breeding if at all possible. The logic was turn the lights down as low as they could go and firstly see if it needs any NPK at all which had the bonus of reducing the salt content of the water. I carried this on always going slight increase dose NPK first for a week then light up another setting and so on and so forth until I hit a point where there was some dissolving of leaves at substrate level so I took the decision to add a little co2 which in turn reduced the TDS quicker, I guess by the increased plant growth. I've kept this up until the light is now 100% and things are running fine with roughly a quarter of what would be considered as EI dosing.

Doing things this way, gradually building up the plant mass to I hit a point of apparent equilibrium seems to have worked out better than the tanks where I have pumped loads of co2 and non limiting ferts in from the off. The other tanks I've set up with an abundance of everything shouldn't have had issues (on paper anyway) but did. There seems to be a period at the start up where eutrophic dosing and high co2 is looking for problems and a slower start up is a better way to go, for me anyway. The moral of the story is probably if you're going down this route you need to implement it properly and it's a fine line to be walking. But there's another way of going about it and definitely more ways to skin a cat.


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## alto

Guess that puts my lazy ass Science person in place 
Who knew that dissent was so personal 




ceg4048 said:


> If folks want to maintain their fear of NO3, which is actually *natures way of detoxifying the environment against the highly toxic NH3 and NO2*, then there is nothing that can be said to change their opinion.


How is this relevant to purposeful additions of nitrate  



ceg4048 said:


> I reiterate that being paranoid


Your words
Never mine


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## alto

sciencefiction said:


> I think the nitrate toxicity issue in high vs low flow systems is oxygen levels in the filters.





dw1305 said:


> I assume it is, faster flow would give you system with more dissolved oxygen, via a larger gas exchange surface.



Poor methodology if dissolved oxygen wasn't taken into account, I assumed the direction of the author was towards N modification of oxygen carrier (proteins) thereby reducing available blood oxygen levels


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## alto

Gaina said:


> That's very reassuring, thank you.  I am very conscious that panicking and taking drastic action would probably do more harm than good so I'm more sure of what I need to do next, thank you.



This was directed to ian_m

@ *Gaina*
I want to apologize for inadvertently instigating a serious thread hijack


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## sciencefiction

alto said:


> Poor methodology if dissolved oxygen wasn't taken into account



Dissolved oxygen was monitored from what I read but how does one measure dissolved oxygen in a filter? They monitored the water itself.


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## Gaina

Hello everyone! Thank you SO much for all the replies. I'm sorry I haven't been around to reply to them all, for someone reason AOL hasn't sending me notification of replies. 

I've added two pots of amazon frogbit, changed to a better liquid fertiliser and the plants have really rocketed away, thus consuming more nitrate.  Curiously, I also switched to a different test kit and I find it much easier to read and I'm confident nitrate levels are in the 'safe zone'.


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## Gaina

alto said:


> This was directed to ian_m
> 
> @ *Gaina*
> I want to apologize for inadvertently instigating a serious thread hijack


 No worries, it passed me by.


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