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Old 06-05-2005, 05:48 PM
jet
 
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I used powdered calcium carbonate. There is no more obvious residue
left in the tank, so hopefully it is as hard as it will get. I expected
to get a higher CO2 levels than this. At 4 KH and 7.4 pH I'm only
getting 4.8 ppm of CO2.

I need to come up with a better way to add the powder at the next water
change. I'm thinking of branching a line off one filter return and
running a very low flow through a bottle DIY reaction chamber with the
calcium carbonate in it. This should eliminate the large swing of
adding the unbuffered powder all at once. It will also give me a bit
more control over the hardness. I can't see going though this bit every
water change as the CO2 tries to catch up with the carbonate.