Thread: Sudden pH drop.
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Old 16-10-2004, 01:21 AM
Michi Henning
 
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"Brian S." wrote in message
news:fEXbd.245812$MQ5.118394@attbi_s52...

For example, I have been running a yeast system now for about two weeks.
When it bubbles in, it will bubble in at an average rate of about one bubble
per 7-12 seconds. However, it seems that the Co2 sits in the "bell"
container that I have fastened to the side with suction cups forever.

[...]
But, I let the yeast production fill up the "bell" container as the Co2
tablets did, then I un-hooked the yeast Co2 generator to conduct my "test".
I let it sit for over 24 hours and only about HALF of the so-called Co2 was
disolved into the water.

So, basically I am wondering if yeast also expels other gases other than
Co2.


Not that I know of. If there are any other gases, they'd make up only a tiny
fraction of the total. What is more likely, I suspect, is that you are seeing
air in your bell: when you initially set up the CO2 bottle, the air space above
the yeast mixture and the air in the tubing are, well, air. So, initially, your
yeast system will produce mostly air and, for a while, will produce a mixture
of CO2 and air. If you see your bell emptying only half way, that simply means
that about half of the gas you put in was air, and the other half was CO2.

If you let the yeast system run for a while (and keep the bottle and hoses
sealed,
so no air can get in), then empty out your bell and refill with what comes out
of the yeast system, I'd expect to see virtually all of the gas dissolve,
because
virtually all of the gas should be CO2. And CO2 cannot help but dissolve in
water, at least at the CO2 concentrations you need in a planted tank. I'm
not aware of any mechanism that could prevent CO2 from dissolving, unless
you saturate the water with CO2, at which point no more CO2 will dissolve.
(But, by the time you reach saturation point, all the fish will be long since
dead...)

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com