Temperature effects on DIY CO2

Hi all-

I just wanted to comment on my startup with DIY co2 and see if anyone has
had similar experiences (since they don't necessarily mirror those on the

I set up a 2 liter bottle with a drilled cap and filled it with ~1tsp yeast
(dry yeast), 3/4 cup of sugar, and filled the bottle 3/4 with water. I was
careful not to use hot water as it kills the yeast and let the bottle sit
for a few hours. It took about 24hrs sitting in the kitchen before consistent
bubbles appeared and still it rather burped than bubbled. This mix sat for
a week hooked up to a pitcher of water (just as a test) and I finally decided
to hook it up to my tank. I placed the bottle under my flourescent hoods
(which happen to over hang the tank on the side by 9") and connected it to
an airline/airstone that I ran into a spare UG lift-tube with associated
elbow joint/head piece (used when the UG filter is run with airstones). Note
I am not using an UG filter- I just stuck the tube into the gravel in the
back corner. Well, the generator began to bubble overnight and it was gratifying
to finally see a burst of bubbles every 4-6 seconds. The one thing I noticed
at night (when I got up to check the pH) is that the generator puts out little
if any co2 when the lights are off. No one has ever mentioned this and I'm
assuming it's probably because our room temp might be lower than others? I don't
think it gets below 70-72 though. I thought this was sort of a
nice benefit since the plants don't really need the co2 at night and so far the
pH hasn't changed much at night. (it's tough to match colors at 3am) Any
one else see this big reliance on generator temperature? Regardless, my plants
are happy and bubble within 2 hours of the lights going on. 

Just as a side note- if you're looking for a cheap reactor to hold you over
until you can build something better try the lift tube idea- the elbow holds
most of the bubbles until they dissolve. For small tanks (this is a 29)
I think it works great.