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Re: CO2 accumulation under glass cover

From Dave Gomberg:
>>>WRONG!  I lost a beautiful community tank full of fish to this assumption. 
>>>The excess CO2 accumulated between the water surface and the cover glass
>>>until all the O2 had been displaced and the fish asphixiated.  You DO have
>>>to worry about too much CO2.  Unless like George you do not use a cover
>>>glass (am I right there George?).
>>All you need is a small gap in the cover glass to fix that.  Is there any
>> reason other than water evaporation to have a cover?  If not, you don't
>>have to seal it to contain the majority of the evaporation.
>WRONG AGAIN!  I had a one inch gap.

Wait...if what you're saying is true, George's fish should have died long ago
even if he had no cover since the CO2 would have displaced the O2 in the space
above the water but below the lip of the tank...what's a 1 inch gap to a gas?  
We're not talking about liquid CO2 here, it's going to have a lot of motion, 
mixing with all the gasses in the room.  The only way you'd accumulate that 
much CO2 is to pump so much into the space above the water that it can't 
dissipate faster than it is replaced (possible with a CO2 tank, mind you).  

As it is, I've had a cover with the same 1 inch gap for months, no problems.
I do have a yeast CO2 reactor, though...no chance of pumping too much CO2 into
the airgap under my glass cover.

Carlos Munoz   
cmunoz at crystal_cirrus.com