re: CO2 input into powerhead

>Anyway ... after about 10 or 15 minutes I noticed small amounts of fine
>bubbles coming out my powerhead & after about 30 mins the yeast + sugar
>mixture was foaming quite a lot - this normally takes about 2 hours to
>happen.  It is not a particularly warm day in Madison WI today (actually
>quite cool & raining) so I can only assume that the "sucking" action of
>the powerhead is causing the reaction to go faster.  Is this good?  It's
>been running for over an hour yet & neither pH or CO2 concentration in 
>the tank have changed.

A couple of guesses:

1. You may have used a lot of yeast.  (Way too simple, this couldn't be it.)

2. The lower pressure could cause the following situation:

Low pressure           -> higher CO2 evaporation
higher CO2 evaporation -> more neutral pH
more neutral pH        -> yeast is healthier
yeast is healthier     -> yeast produces CO2 faster

3. You may be actually producing the same amount of CO2, the lower pressure 
just makes the bubbles bigger.

Could be any, none, or a combination of these.  

David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc.
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