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Re: controlling DIY CO2
On December 13, 1997 Noel Llopis wrote:
> Even though I haven't created any sort of CO2 reactor yet, I believe that
> I'm getting too much CO2 in the water.
Gee, I don't remember hearing anyone report too much CO2 from a DIY system
> I didn't think I had particularly soft water
> either (I even thought it was on the hard side--I'm in Amherst, central
> Mass), but I don't have a measuring kit for that.
You probably should get a test kit for alkalinity or carbonate hardness
(these terms refer to the same thing) and figure out from the
alkalinity-CO2 tables just how much CO2 you have. That might keep you
from trying to fix the wrong problem.
> I would like to hear other people's solutions to this problem. Ideally I
> would like to leave it on, making one bubble every 5-10 seconds or so
> (that way it would last longer too). I've cut down the amount of yeast
> to 1/2 teaspoon while keeping the proportions of the other ingredients,
> but it hasn't slowed it down appreciably. Should I lower it even more?
> Should I cut down on the sugar? Room temperature is around 65F.
You can reduce the yeast dose even farther than that and I don't think it
will change anything. The common 1 tsp of yeast seems to be way more
If you need to reduce the flow from your bottle you should use less
solution. Keep the sugar in proportion to the water. That is, if you
want about half the amount of CO2 you're getting now, then use 3 cups of
water and 3/8 cup of sugar. Also reduce the amount of yeast. Tune the
volume to get what you want.
The alternative to reducing your CO2 production is to increase your
alkalinity. If your CO2 isn't excessive (20 mg/l CO2 or more might be
excessive), then you may want to use baking soda to increase your
alkalinity instead of messing with what sounds like a real successful DIY
> I thought of using some simple air regulator (like the ones used with air
> pumps), but I didn't think that would work.
I use drip-irrigation valves to help regulate the flow, but not to *reduce*
the flow. Don't try to reduce the flow with any kind of shut-off system.
The yeast don't stop because of small increases in pressure, so shutting
off the flow will cause pressure to build in the bottle. Usually this
just causes a leak, but if it builds too far, then things can break.
> For the moment I can only think of unscrewing the tube at night, and
> reconnecting it in the morning. That way I avoid poisoning the fish,
> but it produces quite a pH change.
You can also adjust or increase the water movement in the tank so that
there is more circulation and more surface disturbance at night. That
will drive some of the CO2 out of the water. But twice-daily changes to
a tank setup are a real nuisance.
Of course, another alternative is to just wait. People often report
that CO2 output declines soon after the reactors are started.