# Biological liquid carbon



## Matt @ ScapeEasy (20 Aug 2018)

What do members make of the new biological liquid carbon products such as https://www.aquariumgardens.co.uk/dennerle---carbo-elixier-bio-250ml-2323-p.asp?

Do we think they will be safer for fish?
More or less effective at improving plant growth than guteraldehyde based products?
Has anyone tried it?

I'm sure the opinions will be best and possibly conflicting... be interested to hear your thoughts??

Personally I like the fact it appears safer for th fish and will give it a go... remains to be seen how effective it is. I will try and document it as a single trial of the effects.


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## Edvet (20 Aug 2018)

Could be the next best thing, could be snake oil, could be glutaraldehyde. Nothing mentioned on the package it seems.


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## dw1305 (20 Aug 2018)

Hi all, 





Edvet said:


> could be glutaraldehyde


That would be my guess as well. 

Citric acid (C6H8O7) might be another option, and could be classified as "natural". 

Have a look at the <"Florin Axis"> thread from a few years ago. 

cheers Darrel


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## zozo (20 Aug 2018)

Here is a product review, it's in German. (You might need google translate). But it's stated it does not contain Glut.. And babble indeed something about Citric Acid cycle






https://www.aquarium-welt.net/kohlenstoffduengung-ohne-glutaraldehyd-mit-carbo-elixier-bio/


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## tam (20 Aug 2018)

Their website seems down at the moment, but this PDF (page 78) has more details, looks like no guteraldehyde but that still leaves option 1 & 2: http://jbjaquariums.com/media/2827_Wasserwelt_GB_lowres_einselseiten.pdf


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## dw1305 (20 Aug 2018)

Hi all, 
Thanks @tam, not glutaraldehyde (C5H8O2) then. 

Looks likely to be one of the carbon compounds, from the citric acid cycle, (the image that Marcel (@zozo) posted). Malic acid (C4H6O5) might be an option, it is cheap to buy (like citric acid), so would be an attractive raw material for a carbon supplement. 

cheers Darrel


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## Edvet (20 Aug 2018)




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## tam (20 Aug 2018)

What would that mean it terms of fish/invertebrate safety - is it as harmless as they say?


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## Edvet (20 Aug 2018)

I would guess these are all "weak acids" and would be safe in a tank
https://en.wikipedia.org/wiki/Acid_strength


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## zozo (20 Aug 2018)

A bit further down the site i posted above also is an interview with Dr. Carsten Gretenkord - Biologist and head of Dennerle research and technological development department. He tells a little bit about Glut as a buildingblock for the citric acid cycle in the plant and that this was the basic foundation to research for altenrative ingredients to get the same result wihtout the use of glut. But for obvious reasons can't go into content details other than it works with the Citric Acid cycle and contains next to a number of other ingredients also Potassium and Iron which seem to play a major role in this cycle.


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## tiger15 (20 Aug 2018)

It's not new.  Saltwater folks have been using citric acid as a carbon source to promote denitrification in deep sand.  Another option is alcohol.


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## dw1305 (20 Aug 2018)

Hi all,





tiger15 said:


> It's not new. Saltwater folks have been using citric acid as a carbon source to promote denitrification in deep sand. Another option is alcohol.


That is right, both ethanol (via vodka addition) and citric acid are organic carbon sources, but the reason for the carbon addition would be slightly different between freshwater planted and reef aquariums.

*Marine*
The premise for reef aquaria with deep sand beds or plenums is that, because of very effective skimming, microbial denitrification may become limited by organic carbon (DOC) availability. The additional DOC is the electron donor used by the bacteria involved in anaerobic denitrification. Reef aquarists don't tend to have any plants, or be particularly keen on large volume water changes, so denitrification is one of the few options they have for nitrate reduction.

I've never kept a marine aquarium, but if I did I would definitely have an algal scrubber and ideally some <"Mangrove trees">.

*Freshwater planted*
Plants are pretty leaky structures, and protein skimming doesn't work very well in freshwater, so DOC is unlikely to be limiting. Personally I'm not keen on denitrification in a filter (unless it is a HMF, where you can have successful simultaneous aerobic nitrification and anaerobic denitrification), but it will occur in all undisturbed substrates, and in the zones of fluctuating REDOX values in the rhizosphere, where roots are leaking both carbon and oxygen into the sediment.

Higher plants are pretty effective at depleting NO3, but submerged plants are often CO2 (Dissolved Inorganic Carbon (DIC)) limited.

As far as I know no-one knows the exact pathway through which organic carbon supplements  produce higher levels of photosynthesis, but they seem to aid photosynthesis.

Have a look at @Manuel Arias's posting in <"Liquid carbon....">.

cheers Darrel


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## tiger15 (20 Aug 2018)

What is HMF?

Citric acid is a form of DOC.  In a moderately stocked tank, there is plenty of DOC from from fish waste and left over food, so there is no benefit to add more DOC via citric acid.  Besides, algae thrive on DOC and this is why frequent WC to remove DOC is justified in heavily stocked tanks.


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## dw1305 (20 Aug 2018)

Hi all, 





tiger15 said:


> What is HMF?


Sorry, should have written it out, it is a <"Hamburg Matten Filter">.





tiger15 said:


> Citric acid is a form of DOC


It is, the question would be whether it is the main substance in in <"Dennerle's Carbon Elixier">, and how exactly do liquid carbon supplements aid photosynthesis.

cheers Darrel


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## X3NiTH (20 Aug 2018)

Along with a few other compounds (Citric acid, etc.) the presence of the Acetyl group at the top of the chart Zozo posted is likely Sodium Acetate. I found this really good PDF paper on wastewater treatment and chlorella survival that pretty much lays it all out on the subject of Sodium Acetate efficacy.

ORGANIC CARBON SUPPLEMENTATION OF STERILIZED MUNICIPAL WASTEWATER IS ESSENTIAL FOR HETEROTROPHIC GROWTH AND REMOVING AMMONIUM BY THE MICROALGA CHLORELLA VULGARIS 

The organic carbon supplement that I'm currently using is the Microbe-Lift Bio CO₂ liquid fertiliser (rebadged as a Maidenhead Aquatics Product). It uses a combination of Fulvic and Humic acids.


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## zozo (20 Aug 2018)

tiger15 said:


> Citric acid is a form of DOC



I guess you are slightly mixing things up.. Its Citric Acid Cycle that is a biologic metabolic cycle in the plant that is trigered. It seems that Glut based products do the same within the plant. Reading a bit about this cycle it seems that also Acetic Acid is formed during this proces. And adding vinigar to the tank water also is an not new trick.

Acetic Acid and Alcohol (probably also Citric Acid) are closely related and formed in a biolocal (bacterial) process.. It starts with yeasting, alcohol that finaly becomes Acitic Acid.

Adding Vinigar or Citric Acid to an aqaurium wil both have simular effect. It's not only adding a carbon course as is Alcohol. but it also is an acid lowering the pH. Of what i understood the general concensus of adding acid and lowering pH helps to free Co2 from carbonates in the water which works beneficial on plant grwoth.. Maybe, just maybe i wouldn't be surpised if plants also take up parts from this acid and use it in their citric acid cycle. Till now it is publicaly largely unknown what and how this exactly works in plants. If i remember correctly Tom Barr once stated he knows but was not allowed to go into the subject because he signed a disclosure agreement with Seachem. And till now yet no hobbyist into science figured it realy out. It stops with theories and the usual suspects in how it might work. It still is a well and probablt the best guarded aqaurium secrets.  It seems.


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## micheljq (20 Aug 2018)

I am trying Brightwell Aquatics, FlorinAxis, a similar product (citric acid, citrates and other products) since 4 weeks.  Hard to prove the difference, but my tank goes well.

Continuum Aquatics has a similar products as well :
http://continuumaquatics.com/freshwater_pt/floraviv_prolifera.php


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## Matt @ ScapeEasy (28 Aug 2018)

I have just bought some... one thing that occurred to me though... is there any reason I could use guteraldehyde and citric acid products at the same time?


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## Matt @ ScapeEasy (1 Sep 2018)

Matt @ ScapeEasy said:


> I have just bought some... one thing that occurred to me though... is there any reason I could use guteraldehyde and citric acid products at the same time?


Just bumping this... anyone have any views?  I have been using them both for a week or so now... all going ok so far! Hygrophila polysperma seems redder recently too... not sure if that could be related? I did turn up the lights and dosing a bit at the same time.


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## rebel (2 Sep 2018)

I do wonder whether you'd cause your kH to crash out if adding too much citric acid?


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## Matt @ ScapeEasy (2 Sep 2018)

Even if just doing at recommended levels on the bottle?


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## micheljq (4 Sep 2018)

rebel said:


> I do wonder whether you'd cause your kH to crash out if adding too much citric acid?



That could only happens if you overdose like mad i think, but it's a good idea to check the KH.



> I have just bought some... one thing that occurred to me though... is there any reason I could use guteraldehyde and citric acid products at the same time?



You can, Dennerle for instance, on their web site, encourages to do it, just more carbon for the plants, but less $$ in your pockets.  You are the boss.

Michel.


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## Matt @ ScapeEasy (4 Sep 2018)

Thanks  I'll keep dosing both as my plants do seem to be doing well recently (only been a few weeks) and see how I get on.


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## Matt @ ScapeEasy (11 Sep 2018)

See: https://www.ukaps.org/forum/threads/biological-liquid-carbon.53795/


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## AverageWhiteBloke (4 Oct 2018)

So if humic acid and DOC are beneficial to plant growth would just adding Almond leaves not just achieve the same thing for a fraction of the price with the bonus of the mild sterilising affect and heavy metal binding with tannins not do the same thing?


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## dw1305 (4 Oct 2018)

Hi all,





AverageWhiteBloke said:


> So if humic acid and DOC are beneficial to plant growth would just adding Almond leaves not just achieve the same thing for a fraction of the price with the bonus of the mild sterilising affect and heavy metal binding with tannins not do the same thing?


My suspicion would be that it wouldn't make much difference to plant growth.

The main problem is that nobody knows the exact mechanism by which liquid carbon increases photosynthesis. 

Raising the amount of DIC (Dissolved Inorganic Carbon) definitely increases photosynthesis and the obvious way would be to add CO2, but a compound like <"sodium bicarbonate (NaHCO3)"> also works.

The paper that @X3NiTH posted suggests that some DOC sources (sodium acetate (C2H3NaO2), _D_-glucose) aid the growth of the unicellular green algae _Chlorella, _and _Chlorella_ would have the <"same basic photosynthetic pathways"> as all the higher plants. 

We also know that citric acid (C6H8O7) can potentially act as a carbon source for photosynthesis. Have a look at this thread from 2009/2014 <"citric acid source of carbon">, it covers this area in some detail.

cheers Darrel


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## AverageWhiteBloke (4 Oct 2018)

dw1305 said:


> The main problem is that nobody knows the exact mechanism by which liquid carbon increases photosynthesis.



It's a contentious issue for sure which does seem bizarre at times but at least we are discussing it at some length. You would have thought at some point enough was known about LC and its benefits or not as the case may be but even people at the top of their game still seem to be either undecided or on one side of the fence or the other. I'm in a few facebook groups which I think a few respected members here are also, I've certainly seen them pop up. I'm more of a lurker there than contributor, you can pick up a few handy tips but I'm more there to look at other people's tanks. LC on many of them is not even up for discussion, in fact, just using the term is enough to get you ridiculed! It's fair to say that there does seem to be a bit of campaign going on to get rid LC in certain communities.

Most of the plant growing manufacturers seem to have their own brand of LC going on which begs the question what evidence are they using when manufacturing a product do they have that it has any benefit at all when nobody seems to be able to agree whether or not it actually does.

For instance, we have our own dear old Clive who if you ask him what time it is he will take your your watch apart and show you how it works  he would suggest OD'ing LC to get extra carbon and that you can use LC at quite high doses and its not toxic to Flora or Fauna. Then you get on the other end of the spectrum a guy I come across a lot called Kevin Grant, respected in the community with some serious biology qualifications, friends with Tom, George and even Walsted who has carried out a research paper on Glute and concluded that it does squat. Suggesting any improvement seen is more pacebo and that the carbon you get from using "LC" you could achieve more by actually doing nothing other than oxygenating the water a bit better going on to say that plants that have been exposed to glute show damage to the plants structure. Then you here that Tom Barr is the only person who actually knows and he's been sworn to secrecy by an NDA with Seachem yet I have seen him advise people to use LC to solve a problem yet I got tore a new one by him in a facebook group once for suggesting that someone use LC to add a little bit of LC to a tank that looked to me like it may benefit.

Go figure, it's all a bit confusing for me. now we're on with Citric acid which again no one seems to know why it works and Dennerle won't tell you why  I think the safest option all round is go low tech or go gas. No arguments there and unlike the Forest Gump box of chocolates products that seem to be coming out you do know what you're getting.


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## AverageWhiteBloke (4 Oct 2018)

Sorry if I sounded a bit negative there  but I have more of a simplistic approach to plant keeping and in life in general. Just seems at times that anything that results in a carbon molecule being released these days manufacturers want to cash in on it without any decent explanations why. My rudimentary failed GCSE understanding of it all is that above water there's loads of co2, we like to keep plants because they look nice that in many cases don't want to live under water or wouldn't naturally spend all of their lives there because there's not enough co2 for them to thrive so the answer is to raise the amount of co2 available underwater by dissolving co2 gas in there and controlling how much light forces the speed of growth until we hit a point where hopefully the plant doesn't dissolve through starvation.

A lot of these elixir of life things seem to provide a tiny amount of carbon which could be created by any number natural processes anyway but seem to piggy back in on other chemicals which are at best dubious and at worst known to be extremely toxic to at least humans. Don't get me wrong, I'm not bashing LC, I have some here that I spot dose with now and again which I seem to use less and less these days now that I don't tend to push my plant growth to breaking point I just feel that the best best is to do one or the other at times either gas or don't. Especially when the mantra of most is nature and I tend to find nature and harsh chemicals have never really mixed. In fairness to Dennerle they seem to have a more natural approach to getting that carbon molecule than harsh chemicals.

Anyone who hasn't experienced the joys of suggesting LC in US/Canadian based plant keeping groups and thinks they can fight their corner get yourself in there I look forward to watching the showdown. Just don't forget your crash helmet


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## Edvet (4 Oct 2018)

I never have or ever will use LC, but there are to many which seem to report positive effects to completely be ineffective. Just my 2 €ct's


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## AverageWhiteBloke (4 Oct 2018)

I think the last case I heard in its defence Ed was that the algaecide properties which it definitely possess meant that less spores in the column gave less competition for nutrients and the plant leaves were kept relatively algae free giving better exchange across the leaves which could be true as I've heard George suggesting giving the leaves a wipe during your maintenance regime to remove algae and bio-film. There could be benefits but the argument being it is wrongly labelled and sold as "Liquid Carbon". I tried to argue the point that it does indeed add a minute amount of carbon and that if you have a well gas exchanged tank using atmospheric co2 and this adds a little bit more then it might be the difference a tank right on the edge of low tech needs to improve but tbh I got my blahblahblahblah handed to me and my GCSE chemistry fell apart at the seems. I think using LC also uses up some o2 so not sure how that figures into the above equation.


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## Edvet (4 Oct 2018)

Oh i don't mean to say i understand the chemistry behind it, and i am well aware of "placebo"effects.


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## AverageWhiteBloke (4 Oct 2018)

Edvet said:


> Oh i don't mean to say i understand the chemistry behind it, and i am well aware of "placebo"effects.


Nor me Bro, but if you fancy your chances...

" And these are the calculations for people who wonder how much carbon is there really in Excel... Espen Fjellheim/ Using Glut as a proxy; chemical formula C5H8O2, atomic weight of molecule = 100 (5x12[C], 8x1[H], 2x16[O]). Glut is 60% carbon by mass (5x12[C] / weight of molecule). Excel is approximately 1.5% Glut, according to dosing instructions, max dose, 5ml in 40L => 0.015x5 [mass of water = 5grams]. So dosing (maximum dose) according to instructions, we get 0.075grams or 75 milligrams of carbon in a 10 gallon tank. That's about the mass of 3 large grains of sand (diameter 2mm approx). Plants are about 45% carbon dry mass, dry mass = 5-10% of fresh/wet mass. However, we also know that Glut breaks down into CO2 through bacterial decomposition... assuming total breakdown, 0.075grams of carbon from Glut will give 0.275 grams of CO2. In a 40L/10gal tank; if Glut decomposed immediately in an instant it adds 6.9 ppm of CO2 into the tank, but since we also know it bio-degrades in an aerobic environment with a half-life of 10 hours. Assuming dosing is done upon lights on, and degradation is linear one gets 0.35ppm of CO2 per hour for the first 10 hours. Equilibrium CO2 in non-CO2 injected tanks is about 3 ppm. Natural lakes and rivers have about 2-3 times this amount. (So the idea that equilibrium levels of low tech tanks mirror that of nature is also false for most cases). For CO2 injected tanks it can range between 15ppm to 50ppm. So is Glut a catalyst, placebo, or does the meager 10% additional CO2 assuming ideal conditions make a large difference......"

There's also a sub argument that they call it liquid carbon because of certain restrictions on selling algaecide.


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## Matt @ ScapeEasy (4 Oct 2018)

This is really interesting and I think the 10% carbon vs the cost of the product says to me personally... why bother? I also believe in keeping things simple so that fits with this viewpoint.   I'd be really interested if the same chemistry style calc can be done for citric acid... especially in terms of the %increase in co2 over time as I believe that this product does not break down in the same way during the day... but even saying that now I'm starting to wonder again... well how does it work then!?


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## ian_m (4 Oct 2018)

AverageWhiteBloke said:


> Excel is approximately 1.5% Glut, according to dosing instructions


Newer Excel is not "standard" glutaraldehyde, the material safety data sheet says polycycloglutaracetal (at 2.5%).

Polycycloglutaracetal, a polymerized isomer version of glutaraldehyde. It is claimed that this provides a greater bio available carbon source for plants (compared to glutaraldehyde). Being polymerised it is less reactive whilst in the water, until it gets unpolymerized in the plant/algae.

Normal glutaraldehyde will polymerise in strong aqueous solution but reaction is extremely slow (days/months) and has to be strong solution. Commercial glutaraldehyde, for disinfection use often has something in to stop it polymerising over time.

Polycycloglutaracetal & glutaraldehyde can use used by plants as a carbon source but not algae, which is why it acts as an algicide.

In my experience using both Excel and glutaraldehyde extensively, Excel is a much superior algicide, especially when spot dosing BBA. As for plant growth well no idea.

Also they both smell completely different. EasyCarbo smells the same as Excel.


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## AverageWhiteBloke (4 Oct 2018)

ian_m said:


> Newer Excel is not "standard" glutaraldehyde,



Which is probably the bit Tom can't talk about Ian.


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## AverageWhiteBloke (4 Oct 2018)

Matt @ ScapeEasy said:


> This is really interesting and I think the 10% carbon vs the cost of the product says to me personally...



I guess that depends on whether you run a tank that is just bordering on being pushed for carbon and the 10% could make a difference plus the other benefits I mentioned earlier. I guess more water changes and stroking your leaves could sort that with a reduction in light would achieve the same as adding LC.


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## Edvet (4 Oct 2018)

AverageWhiteBloke said:


> stroking your leaves


How about:


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## AverageWhiteBloke (5 Oct 2018)

Matt @ ScapeEasy said:


> well how does it work then!?



Does adding any acid to any any base not result in a reaction that produces co2? So if you have water that is high in KH and you add something acidic.... Again, apologies for my GCSE Chemistry


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## AverageWhiteBloke (5 Oct 2018)

What was that graph Darrel often puts up where DOC converts to co2 as the PH lowers? Is that related maybe?

Sent from my STH100-2 using Tapatalk


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## Edvet (5 Oct 2018)

AverageWhiteBloke said:


> Does adding any acid to any any base not result in a reaction that produces co2


Nah thats H20 (H+ plus OH-)


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## zozo (5 Oct 2018)

AverageWhiteBloke said:


> Does adding any acid to any any base not result in a reaction that produces co2?



If the water contains a buffer it does.. Afaik for us that would be Carbonates and Phosphates that buffers acids.. But the CO2 produced by this process anything above natural equilibrium will gass off into the atmosphere. Now i do not now if water with lower pH has a higher natural CO2 equilibrium. It likely is related to its kH value.

Iexperiemnted some time with acids with growing crops in the garden.. After reading about beter ion exchange in slightly acidic invironment and this can be achieved by lowering the fert solution pH before you add it. And or also use peat etc. mixed into the soil to lowet it's pH will result in beter producing crop. 

For watering terrestrial plants you can go as low as pH 5 with the fert solution.. 

I also noticed if you leave the readily mixed pH 5 fert solution stand for 24 hours it simply raised back to +/-  pH 7 again.. Than if i tried to lower that again with adding some more acid the party started with the pH+ solution. I never measured kH in those days, but i guess it alters with adding acids, because after adding it again after 24 hours buffering it rapidly and drasticaly crashed bellow pH5 with adding much less acid after that. By experience you learn for example 10 litre fert solution needs x amount of acid to lower it's pH 8 to a certain point. But once it has all buffered and raised again this amount changes drasticaly. If this buffering and raising again id solely a carbonate/phospate reaction with producing co2 that gasses off i don't know, i doubt that because of the crashes i  experienced. 

I should actualy know why i red it dozens of times, but somehow i can't make my brain repeat the excact procedure and formulas.

But bottom line, knowing why is fun but not a need to know. Just knowing this risk is enough not to play with acidic stuf in a fish tank.  If so maybe at very tiny dosages barely affecting the pH. Lowering pH several units, it comes dangerously close to crash point to stabilize it. Which i think is extremely difficult with doing weekly water changes and extremely crash risky with doing very little water changes. 

A guess, lowering pH has more with beter ion exchange in plant v. ferts than the Co2 it produces. Lots of people report accelerated plant growth with adding vinigar to the a planted tank. Personaly i rather skip it, i don't trust it enough and don't want to drive me self crazy with monitoring it in a dairy like a boatswain. Learn to choose the correct plants and grow them in what you get is more forgiving and more fun..


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## AverageWhiteBloke (5 Oct 2018)

I had a similar thing well back in the day zozo before I found out about Indian Almond leaves etc. My water comes out the tap with virtually nothing in it. The only stuff in there is actually added by the water board so zero carbonate. I tried using a waterlife product if I remember called humaquat which added tannins and humic acids which I thought would benefit my cardinal tetras and crashed the system. After that I switched to Tetra Blackwater which didn't lower ph. Now I just use botanicals which are much milder. 

Sent from my STH100-2 using Tapatalk


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## dw1305 (5 Oct 2018)

Hi all,





AverageWhiteBloke said:


> ...... understanding of it all is that above water there's loads of co2, we like to keep plants because they look nice that in many cases don't want to live under water or wouldn't naturally spend all of their lives there because there's not enough co2 for them to thrive so the answer is to raise the amount of co2 available underwater by dissolving co2 gas in there and controlling how much light forces the speed of growth until we hit a point where hopefully the plant doesn't dissolve through starvation.


Pretty much. Something like _Hemianthus callitrichoides _is absolutely <"fine emersed"> at 400ppm CO2, and easy to grow, but requires high CO2 submerged.  





AverageWhiteBloke said:


> now we're on with Citric acid which again no one seems to know why it works


Because all the "LC" molecules, that seem to increase plant growth, are fairly small molecules/ions, I'd assume they all work in a similar way, but you'd need to talk to plant physiologist to find out what the likely mode of action is, and how they get into the plant..
You have:

The acetate ion, CH3CO2−
Citric acid, C6H8O7

Glutaradehyde, OCH(CH2)3CHO (as a hydrate)



zozo said:


> But the CO2 produced by this process anything above natural equilibrium will gas off into the atmosphere


Yes it will, it is just like when you open a bottle of a carbonated drink, the pressure falls and CO2 comes out of solution. If you leave the drink un-stoppered for any length of time it will lose its fizz as all the extra CO2 is lost along its diffusion gradient with the atmosphere.





zozo said:


> Afaik for us that would be Carbonates and Phosphates that buffers acids


Yes, but it would need to be carbonate buffered and then the state of the DIC will change dependent on the pH.

You can see you don't have any more TIC, you always have the same amount, in different forms (regulated by the 400ppm CO2 in the atmosphere).




zozo said:


> But once it has all buffered and raised again this amount changes drasticaly.


That is right, that is how buffering works, it isn't a linear process, it is pretty much stasis followed by a rapid change.





AverageWhiteBloke said:


> Now I just use botanicals which are much milder.


These are the pH titration curves for acid base titrations, it also shows why lowering/raising pH is much safer  weak acids and bases.





It also shows why pH needs some interpretation, if you are around pH7 (or have water with few ions present), small changes in water chemistry (changes to the acid:base ratio) can cause large changes in pH. 

cheers Darrel


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## rebel (5 Oct 2018)

Wonder whether anyone has done any experiments to put the above candidates head to head in controlled tanks?


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## Oldguy (5 Oct 2018)

AverageWhiteBloke said:


> at related maybe?


At high pH CO2 will be as bicarbonates. At very high pH it will be as carbonates (soda lakes)
At low pH CO2 will be as carbonic acid (assuming it exists, its salts exit but the free acid has not, to my limited knowledge, been isolated)
At lower pH it will be there as a dissolved gas. (the dissolved gas will be transiently bonded to water, hence high solubility for a gas)
There is a nice curvy graph which illustrates these relationships. High & low pH's are in terms relative to aquarium fish & plant care.


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## Oldguy (5 Oct 2018)

Darrel has piped me to the post with his graphs.


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