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Re: CO2 problems
Hey, folks, we're forgetting some of the basics here. Adding CO2 to your
aquarium is not like adding fish food - you need to think about what you are
doing and exercise caution and common sense. Some aspects of CO2 are
counter-intuitive, so a little uncommon-sense would be good, also. It wouldn't
hurt to read a little about it before jumping in with both feet (check my web
>But, you should be aware that adding CO2 to the water can and *will*
>cause the pH to drop. Depending on how much CO2 is entering the tank vs
>how much the plants can consume will determine your drop.
The plants generally consume very little compared to how much is injected. A
relatively large amount is injected to create a sufficient concentration to
allow efficient uptake by the plants. The real determining factor in your pH
drop is the carbonate hardness of your water. This is commonly known as KH and
is usually measured with an alkalinity test. If your water has low carbonate
harndess (very soft), a little CO2 can change the pH drastically. You should
determine your KH *before* you start adding CO2 and use the ubiquitous pH/KH/CO2
tables to determine the proper parameters for your setup.
>My 20 gal went
>from a pretty steady 7.0 to down in the high 5s. I haven't checked my new
>55 setup yet.
Gee, maybe it might be a good idea to check pH once in a while when you are
>The main problem with DIY CO2 is it's uncontrollability.
It's easily controlled, but the aquarist has to have some input into the
process. CO2 can be dangerous to your fish and you should be careful when using
it. Did I say that before?
>Also, many systems can shut off the CO2 at night (well, when the
>lights go out, anyway...), when the plants don't use CO2.
A pointless exercise. The CO2 used by the plants is small compared to the amount
lost to the atmosphere when levels are in the 15 mg/l range. You get far
smaller pH swings if you leave the CO2 on all the time and control the flow
I wonder if any of the scientists among us have any info on how much CO2 plants
use when they are strongly photosynthesizing? I have evidence of how fast it
diffuses into the atmosphere.
George Booth in Ft. Collins, Colorado (booth at frii_com)
Need Info? http://www.frii.com/~booth/AquaticConcepts.htm