# NO3, PO4 and the case of the Reef Tank fiction as fact.



## hinch (4 Dec 2012)

OK so not strictly a planted tank thread but certainly a water chemistry thread and we have a few people here who are a bit good with chemistry.

In the planted tanks we know that we have to dose Nitrate and Phosphorus into the system to enable the plants to grow and maintain a high water quality.
In a fish only tank we know we have to change water often so as to keep the Nitrate down as there's nothing to absorb the Nitrate out of the water column and while its less toxic in high concentrations its bad.

This brings me nicely onto my next confusing point Reef Tanks!

There are lots of hearsay in the reefing world and lots of sweeping statements with no technical backup/research.  People believe them as gospel in the same way as we believe light colour makes a different to plants  I'll list a couple below before I get onto my main point.

Bioballs in filters are nitrate factories.
PO4 causes algae.
Vodka is the best source of carbon which removes PO4 and NO3.
Diatoms are caused by PO4.
Test kits are vital as they're the only accurate way of measuring Ammonia, Nitrites, Nitrate, PO4, TDS, Cond etc etc etc.....


First up PO4 causes algae!
I can't do the sciencey thing as organic chemistry confuses me massively however I can understand general principals.  So we know PO4 when combined with other minerals will encourage plant growth and algae will grow instead of plants if not provided with enough carbon food via co2 for the plants to convert all the minerals to growth.  ie: excess/unused minerals will grow algae instead of plants.
So in the reef area people spend fortunes (litterally! go check the prices) on stuff like rowaphos, skimmers and other chemicals / reactors etc just to add and/or remove PO4.  Could the same effect not just be resolved by having an excessive amount of plants or encouraging algae growth somewhere which would then use up the minerals in the tank you can then simply remove the plant and therefore remove the PO4 from the equation.
A few people are now experimenting with stuff like Chaeto algae growth or running algae scrubbers in their sumps to remove the PO4 etc but they're running it in conjunction with the other more traditional sources.
Would it not make sense to simply have the entire sump as a massive algae growing tank where dirty water goes in the plants in the sump absorb all the nasties and simply return clean water out the other end?  Exactly the same way we do with plants when we say plant heavy and you can support more fish/require less actual filtration.

Vodka is the best source of carbon which removes PO4 and NO3.
This kinda ties in with above I guess people are dosing 80% proof + vodka directly to their tanks as a carbon source as organic carbon removes NO3 & PO4!
I can't decide if this is bullshit or not as people are reporting results but to me dumping vodka in a tank is a bad idea.  Surely if you have proper mineral removal from say algae removal above you wouldn't need additional carbon sources to remove it?  Failing that why use vodka surely the liquid carbon we use in planted tanks is a highly concentrated organic carbon source could that be used instead of vodka.

Test kits are vital as they're the only accurate way of measuring Ammonia, Nitrites, Nitrate, PO4, TDS, Cond etc etc etc..... 
This is my personal bug bear and they swear by test kits blindly!  I generally ignore them and as long as I have the right salinity of water and right PH then I ignore everything else and see what the corals/fish do as to what I need to adjust but I still use all the equipment as its whats considered required and tbh I know no better to argue with people.  I do know that the skimmer removes gunky stinky stuff etc and that stuff dies if it stops working, but I don't really know why.  I do know based off what Clive/Darrel have posted previously though that its almost impossible to measure some of these things - that the Reefers use as reference points and gospel - with a £30 over the counter dip strip kit.



At the moment even my little reef tank has nearly 3k of equipment running just to "keep the water clean" the cost not only of purchase but also of running all the pumps and equipment and constant cleaning/refilling/ingredients etc is quite honnestly scary I daren't add it up.
I'm trying to find a better way of keeping my tank stable while reducing the maintenance and the costs! I'd much prefer to harvest a bucket full of algae once a month than have to clean skimmers and refill reactors and do massive water changes once a week.



A little related reading

http://www.advancedaquarist.com/2012/3/chemistry
http://reefkeeping.com/issues/2006-09/rhf/index.php
http://www.advancedaquarist.com/2003/8/chemistry
http://www.ultimatereef.net/forums/show ... p?t=588481

Again not plant related but chemistry and tbh I trust a few people here alot more than I trust 99% of the reefers on reef forums who bang on about you have to buy XXX bit of kit for £000000 because it keeps your PO4 level at zero with only £000 of media a week!


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## gmartins (4 Dec 2012)

I'm not a reefer but the way I see it is that they use PO4 as the limiting factor. That is, by removing PO4, they limit the amount of algae that can grow. Reducing light is not an option as this would affect the colour of corals. The use of carbon may be related to the fact that they stimulate photosynthesis until algae consume all the PO4 available? Not sure this is a good strategy though as I suspect that marine algae can probably uptake all the carbon they need via carbonates. So marine algae may actually not be carbon limited, as in planted tanks.

I am sure that having a good filtration with chaetomorpha or mangrove trees will do a good job in removing nutrientes from the water. The only problem is to calculate how much biomass is needed...

Not sure about the test kits. Although the reactions involved must be different (salt vs fresh water) in many cases, I would still be very suspicious of their results.

I also have this idea that reef tanks are nearly always overstocked. Not only a large number of animals (inverts and fish) is used but also fish are much larger and consequently have a much greater bioload. In addition, reefers often feed fish highly enriched foods (e.g. frozen). This means that removal of PO4 via algal consumption may not be sufficient given the high levels of input, and hence the need for all the chemical filtration. I'm speculating here.

GM


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## Clifford (4 Dec 2012)

I'm sure quite a lot of "reefers" use planted, lit, sumps for removal of excess nutrients.

I considered a reef tank a few years ago and there was much talk of mangrove roots, miracle mud and macro algae (caulerpa prolifera) at the time.


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## hinch (4 Dec 2012)

it seems very split at the moment. some do some don't but its very rare you find anyone purely with vegetation sumps you'll find people running pure chems+equipment or hybrids of both but never the other way and pure plants/algae


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## plantbrain (5 Dec 2012)

hinch said:
			
		

> it seems very split at the moment. some do some don't but its very rare you find anyone purely with vegetation sumps you'll find people running pure chems+equipment or hybrids of both but never the other way and pure plants/algae



This is due a back up system in case one does not balance the other.

I run most heavy on the refuges, then have a mega skimmer also.
But as long as the skimmer does not get much skimmate, not much reason to run it. 
I use it on the initial set up phases, and if any larger changes are done, or if I remove a lot of biomass from the refuge or main tank.

PO4 is okay to about 0.2-0.4ppm for most systems before diatom blooms occur.
0-0.2ppm is better.

So a small pulsed dose as food or as KH2PO4 is used. 2-3x a week etc. 
I prefer food over inorganic chemicals.

Bioballs are fine as NH4=> NO3 factories. NO3=> DBS in the refue=. N2 gas and plant biomass.

PO4 grows plants at lower ranges.

Plant biomass leaches photosynthate, which is a much better form of reduced carbon for bacteria to not be carbon limited. This is one reason why Refuge's work well.

Agreed on higher than 0.4ppm PO4= diatom bloom, I've not found otherwise when dosing inorganic KH2PO4.

I disagree about the test kits, it depends on your management goals and question/s.
Like EI, I can do a 30% weekly water change and dose, feed whatever I chose........but Reef folks hate mixing water and salt mix cost $. But I can mix 100 Gallons of water in 45 minutes or less and of that 45 min, only 3-4 are actually doing anything.

NH4 gets attacked faster than you can measure it, the residual and the production are cycled before your test kit measures it.

Main things to look at and watch; Alkalinity, Ca++, water currents, careful feeding and temp stability. 
With frequent water changes, there's little need for test kits. I dose a little, but not much.

I think many reef folks spend way too much $ on test kits, and labor, process controllers, reactors etc.
Not enough on the good old water change and salt mix. :idea: 

KISS


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## hinch (5 Dec 2012)

> Main things to look at and watch; Alkalinity, Ca++, water currents, careful feeding and temp stability.
> With frequent water changes, there's little need for test kits. I dose a little, but not much.
> 
> I think many reef folks spend way too much $ on test kits, and labor, process controllers, reactors etc.
> Not enough on the good old water change and salt mix.



I didn't want to quote the whole thing.

but this is kinda my problem they're too much params this params that. I tend to look at 2 things PH and salinity thats pretty much it but I still setup blindly all the rest of the equipment and its all very high maintenance especially since its in the lounge so on a carpeted floor.  I want to cut down maintenance and reduce the running costs and running noise.  But reading nonestop on reef forums about all the params and alot of what they say is counter to what we do in planted tanks insome cases such as "test kits" they swear blind by them i mean paying like £200 for "good" test kits makes me cry especially when we know from planted tanks that they just don't work for some molecules.  If I can get away with basically ripping everything out of my sump and just replacing it with cheato and live rock rubble and remove everything else i'll be happy tbh.

Bit reluctant to use a DSB as concerned how you'd get flow through the lower levels of the dsb to stop you getting a hydrogen sluphate(sulphide?) build up as it compacts.  Again I know from a planted tank that a deep sand bed will eventually go anaerobic and become toxic

Was hoping to get some response from you / clive / darrel that could confirm if I was thinking right or not


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## dw1305 (5 Dec 2012)

Hi all,
I know nothing about marine in practice unfortunately other than that high PO4-- levels can inhibition of calcification of corals, but I don't know at what level this starts.


> If I can get away with basically ripping everything out of my sump and just replacing it with cheato and live rock rubble and remove everything else i'll be happy tbh.


Theoretically I think you can, possibly dependent upon your stocking, whether that is true in practice I've no idea. 
I may have misunderstood this but if you have "live sand" and continue to top up the organisms, doesn't this mean that it never goes totally anaerobic?

cheers Darrel


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## hinch (5 Dec 2012)

thats a good question I can't find enough information but as far as I can tell live sand just means it contains natural sea bacteria instead of being dead sand not that it contains critters for turnover/movement.


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