re: Info on C02 Injection Needed

>From: Marty Durkin <durkin at stsci_edu>
>I have setup a DIY-Yeast C02 Injection system in a
>1 gallon bucket to test things out.  The water initially
>had a ph of 7.5, a KH of 3, and a GH of 6.  The C02 injection
>has actively been injecting CO2 through an airstone since
>last Saturday.  As of Wednesday evening, the ph had dropped
>to 4 (I used 2 separate test kits to test it).  The KH and 
>GH have remained unchanged.  By the way, I was using a 1 gallon
>bucket as a test case to see how long the C02 would last and
>what changes in water chemisty I would notice.
>My question is, since I will be using this on a 55 gallon tank, 
>will the ph drop as drastically since I am dealing with a much 
>larger volume of water.  By the way, my ph, gh, and kh of the 
>tank are the same as those mentioned initially and have remained
>stable for several years now.

I'd probably go ahead and bump my KH up to at least 4 if the pH starts to drop
too much, but beyond that, I don't expect that you'll have any real problem
with a pH crash on a yeast system unless you're dumping CO2 out in a big hurry.
If you're only using 1 tsp. of yeast, I don't expect a problem at all.  I ran
my 55g tank with two 2-liter bottles (1 tsp. each) for over a year prior to
moving and never had a pH crash (my tap water KH is 5).

David W. Webb in 75F, smoky Plano TX, where the grass fires have people's
allergies in high gear.