Re: Aquatic Plants Digest V1 #187

>From: KB Koh <KB_Koh at ccm_ipn.intel.com>
>Date: Mon, 17 Jul 95 08:35:00 PDT
>Subject: Yeast CO2 questions
>I've just rigged up the CO2 yeast method following recipe posted by
>David Webb. I've connected it to an air-stone while building a reactor.
>Immediately noticeable effect are bubble streams coming out of cutted
>sections of stem plants and reduction in my pH. That must be a good
>sign. Now my questions:
>1) Do I leave the CO2 bubbles coming out at full blast or reduce it with
>the air valve?
Check your pH, preferably first thing in the morning just as the lights are
about to come on...if its too low you should reduce the CO2 input or
alternatively, add a little aeration. A small air hose without an airstone
into the tank will reduce the CO2 marginally and may be what you need.

>2) Will reducing bubbles increase the preassure in the bottle and
>explode like that was posted in the last few mail.
No. As long as the airstone isn't clogged the pressure can not greatly
excede that required to push gas through the air stone. If the stone does
get clogged the next thing to go would be the cork, which will get forced
out long before the bottle explodes.

>3) Is it true that if I reduce the amount of yeast in my next mixture,
>would it last longer but with less bubble rate? Is there a catch to
Not really. The yeast will multiply fairly rapidly and reach their
equilibrium concentration in a day or two regardless of their initial
concentration (exponential growth and all that). What I do is almost NEVER
make a NEW mixture. I stir the mixture well to suspend the dead yest cells
and then just drain out 3/4 of the old liquid and add fresh water (straight
from the tap) and sugar. The yeast left over in the liquid starts to
multiply again and I'm back in full production by the end of the day (saves
money in yeast that way). But every couple of months I start from scratch
just to be sure thhe bacterial levels aren't getting to ridiculous.

internet email: Grant.Gussie at phys_utas.edu.au
www page: http://reber.phys.utas.edu.au/~gussie/