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Re: Bioplast CO2



David wrote:
>Back on the CO2 front. My new Bioplast is bubbling away at circa 2 bubbles a
>second. pH is circa 6.8 -- 7.0 in the day, 6.5 at night. kH is nearly 4 I
>think, and gH is also 4. No measurable Phosphates. Nitrate holding steady at
>5ppm.  Since adding the CO2 injection two days ago, these numbers represent
>really a minimal change from before the CO2 i.e. pH 6.8 - 7, gH of 4 and kH
>of 3.

Adding CO2 will not change GH or KH. If CO2 is being effectively dissolved, you 
should see pH go down.  If you see no pH change:

1) Your CO2 "reactor" (whatever means you use to get CO2 mixed with the water) 
is not very efficient. I forgot how large your tank is, but 2 bps does not sound 
huge unless you have a very efficient reactor or a smallish tank. Don't forget 
it will take more CO2 to raise the concentration initially than it will take to 
maintain it. This is one of the reasons it it not smart to turn CO2 off at 
night.

2) Your pH test kit does not have enough resolution to distinguish between 
equilibrium CO2 and somewhat higher CO2.  

You also may be seeing a combination of 1 and 2.   


George Booth in Ft. Collins, Colorado (booth at frii_com)
  http://www.frii.com/~booth/AquaticConcepts