Re: does the presence of shell...

[Paul Sears <psears at nrn1_NRCan.gc.ca>]

	The presence of calcium in the water does _not_ affect the solubility
of carbon dioxide in the water.

	Calcium carbonate solid in an aquarium will react with CO2 in the
water to give Ca++ and HCO3- ions in the water, i.e., the hardness will
increase, but an equilibrium will be reached, and at that point the
CO2 concentration in the water will be the same as if the CaCO3 hadn't
been there.

-- 
Paul Sears        Ottawa, Canada