Re: Newbie Designs and disrespected substrates -- At a loss re CO2

["S. Hieber" <shieber at yahoo_com>]

> I thought you lost CO2 with aeration due to gas
> exchange?) None of the fish ever shows any discomfort 
> with the Oxygen levels day or night.  What am I not 
> understanding here?


IN a tank into which yo inject CO2, you are getting the
level in the water up above what it would be from good
exposure to the aire and the CO2 that's in the air.  The
room air supports only a relatively meager amount of CO2
inthe water.  So promoting gas exchange between water and
air (surface agitation with the sruface exposed to room
air) will deplete the CO2 level in a CO2 injected tank. 
The water is rich with it and it passes of to the air that
is not so rich with it.  

But in a tank that isn't CO2 injected, the "extra" CO2
comes from the fish respiration and is generally at pretty
low level and the plants use it up.  So promoting gas
exchange with the air helps to replenish the CO2 back the
relatively meager levels that are supported by the room
air. 


Scott H.

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