Re: Yeast Explosion

>From: "David Huie" <David.Huie at Bentley_COM>
>Subject: Yeast Explosion
>     I have a problem that I'm hoping someone can give me suggestions on.
>     I've had all the fish in my tank killed by acidosis...twice now.  Both 
>     times were as a result of massive pH changes due to my inaccurate CO2 
>     injection method.
>     The first time, the tank just ran out and the pH went from 6.2 to 7.8 
>     in about two hours.

What's your KH?  With a KH of 4, I bring the pH down from about 7.6 to 7.0.
That's not too big a swing for most fish if the CO2 runs out.
>     The second time, last week the whole CO2 tank vented into the aquarium 
>     at once--a one inch shell of ice on the CO2 canister was a bit 
>     bizarre.

My first thought would be that you have a really poor regulator.  Most
folks running open-loop (i..e., without a pH controller) use two-stage
regulation.  The first stage brings the pressure down to 10-20 PSI.
A second stage (needle valve) controls the actual rate of CO2
injection into the tank.

>     I won't cope with another mass fish death due to massive pH 
>     fluxuations and I don't think I can afford a fully-automated CO2 
>     injection system--and I won't go back to my old unreliable yeast 
>     method.  Isn't there a reasonably affordable reaction chamber 
>     available to help dissolve CO2?  Even That Fish Place claimed to have 
>     no such thing.  I had to makeshift--and it turned out to be the death 
>     of my fish.

A diving bell a la Tetra will give you an upper limit on the rate of
CO2 injection, provided you have a somewhat *reasonable* regulator.
With the bell method, the rate of CO2 injection is determined by the
surface area of the CO2-water contact, and if you inject too much, the
CO2 will simply escape.

Shaji Bhaskar                                              bhaskar at bnr_ca
BNR, 35 Davis Dr., RTP, NC 27709, USA                      (919) 991 7125