"Anton Valouev" wrote in message
...

I am wondering if it is ever possible that CO2 in the filter would
inhibit
nitrifying bacteria.

No, bacteria is cool about it. There is even anaerobic bacteria there that
leaves only when there's no oxygen around. I doubt that you can bring the
c02 level so much up that it will kill the bacteria before killing the
fish.



Thanks. Do you diffuse CO2 into a canister filter? -Bruce Geist