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Re: Aquatic Plants Digest V3 #952
> For the life of me, I can't figure out why agitating the surface could cause
> *any* significant loss of CO2 under those fairly normal circumstances. The CO2
> in the trapped air and the CO2 in solution will still be at equilibrium, and
> there is no place for much CO2 to get away.
> Even in open-top tanks, the heavier CO2 concentrates on the surface and only
> slowly diffuses into the room. *If* you had an active fan blowing air across the
> surface, and *if* you did not have any cover, your evaporative losses and CO2
> depletion could be high. Otherwise, I'm having a problem understanding what the
> problem really is. ;-)
I don't know why, but I can give first-hand evidence that water surface
agitation will cause CO2 loss. It happens with any kind of splashing on
the water surface. I've run a Whisper Diatomagic filter on my planted
tank. The Diatomagic has a water return that acts like a regular faucet
with one of those diffuser things that breaks up the water. As the
filter runs, I can sit there and watch the pH rise even though CO2 is
being injected. I can say that even an Eheim surface extractor will do
it, although very slowly.
It's not anyone's imagination.