New pinned article - CO2

[George Farmer]

At last I've managed to finish off my CO2 article. Hope you find it useful. Post any feedback/questions here.

http/www.fishforums.net/index.php?showtopic=105266

 

[Bloo]

Fabulous ! I LOVE pinned articles.
Great stuff

 

[BLASK]

Excellent work!

I really enjoy reading stuff like that

 

[iggy01]

First rate article gf!

CO2 is often overlooked or misunderstood. I'm sure this will help many people.

 

[zig]

Excellent gf........so good i read it twice Honest

 

[nodding_dino]

great article gf!

(you've doubled up on a paragraph though ) )

Carbon Dioxide Levels and other Water Parameters

Recommended levels of CO2 are 20 to 35ppm. It is important that these levels remain fairly constant, as fluctuating levels are known to cause algae. Higher levels are sometimes used to fight off algae – it is known that levels higher than 40ppm can block the enzyme production in the algae cells. However one must pay attention to the behaviour of the fish as levels higher than 35ppm are known to cause health issues.

One of the consequences of injecting CO2 into water is that it produces carbonic acid. This acid will reduce pH so it is important that the water has sufficient buffering capacity (Carbonate Hardness or KH). Ideally the water should have a KH of at least 2 degrees or 40ppm.

Measuring CO2 levels is straightforward using accurate pH and KH test kits and reading off the result on a pH / KH / CO2 table. There are many available on the Internet (see my signature). Note that you cannot alter your CO2 levels by simply changing other water parameters. I have known people to use pH buffers with the belief that the lower pH will increase CO2 levels. This seems to make sense if you look at a CO2 table but pH buffers replace KH therefore rendering the reading as useless. pH and KH are intrinsically linked – it is this fundamental law that allows us to measure CO2.

Another misunderstanding is that low KH results in higher pH swings. This is not true – see for yourself using a CO2 table, note the actual swing size is identical given the same CO2 levels for any pH/KH. The only issue with low KH is that it may result in a pH crash, however I know of successful planted aquarists (zig for one) that run with KH 1.5 with no problems. I can only assume that if one performs large regular water changes then pH crashes should not be an issue. Perhaps it is the accumulated acids caused by nitrification etc. in a “less than well-maintained” aquarium that cause the pH crashes more than the low KH alone. Just a thought.

Recommended levels of CO2 are 20 to 35ppm. It is important that these levels remain fairly constant, as fluctuating levels are known to cause algae. Higher levels are sometimes used to fight off algae – it is known that levels higher than 40ppm can block the enzyme production in the algae cells. However one must pay attention to the behaviour of the fish as levels higher than 35ppm are known to cause health issues.

Another benefit of CO2 is that the reduced pH levels can often be beneficial to a lot of tropical fish. The majority of freshwater tropical fish originate from water with soft and acidic water, examples include Tetras, Rasboras, Angelfish, Discus, Barbs, Corydorus, Loaches, Killifish, Gouramis, Bettas and most species of Catfish i.e. Plecs.

 

[George Farmer]

Thanks guys.

ND - I've edited, thanks.

zig - What do you make of my low KH/pH crash comments?

 

[zig]

Thanks guys.

ND - I've edited, thanks.

zig - What do you make of my low KH/pH crash comments?

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I think it has to be the case gf, i cant offer any other explanation for it, its something thats puzzled me for ages, it has to be the 50% water changes, mind you i have only been adding small amounts of nitrates and have had a small fish load up to now.

But in the last few days things have changed in my tank quite a lot, and i have been thinking about this further as ive been increasing my nitrate dosing to keep the tank above 15ppm, before i was dosing 10ppm letting it drop back to 7-8ppm and topping it up again, but now i want it above 15ppm, and i would say it gets to about 20ppm at some stages during the week and then drops back down, so effectively i have doubled the nitrate level.

But i have also doubled the fishload in the tank in the last couple of weeks (i had to seperate livebearers that i had bred as i could'nt afford any more fry and i dont have the room in existing tanks for any more fish without being overstocked) so this would have an effect on the nitrate levels as well, so it is something i am keeping an eye on, but i just wonder where the fine line is before the levels of nitrate have an effect by dropping my Ph, but i feel this is very gradual and over a long time rather than the course of a week and obviously i will continue to do 50% water changes.

But yes it is interesting, maybe im threading that fine line allready, i think when i go pressurised i will have to buffer the water just to be on the safe side of things, because i would imagine keeping the co2 at much more consistant levels and probably much higher (id probably run it at 35ppm minimum) than i am attaining now with the diy units this may throw me over the edge, but im not in any position really to do any live tests as it were to find out.

 

[qwikimpss]

And ANOTHER great article on aspects of keeping successful planted aquariums...too close after Zigs EI artice! I'm still trying to digest it!