3/4 cup sugar, 3/4 tsp yeast, and water till 3 inches to the top of a 1.5 litter can. how long will it take to start producing? should I connect it when it starts to produce? whats a sign of it producing?
The reason why you want so much water is to protect the yeast. Eventually they'll produce too much alcohol and will start dying off. Try 2 cup sugars, 1/4 teaspoon of yeast, 1 tbls baking soda and fill the water up to the curved section of the bottle.
Before you try that, check your seals for leaks. Get lightly soaped water and spray or rub it on with a sponge. If it starts to bubble, you have a leak. You can seal it with silicone. Personally i don't use any adhesives to seal. I drill the hole smaller than the diameter of the silicone tube and force it through. That usually keeps it nice and sealed. This doens't work with co2 resistant tubing because it's too hard.
Follow snyper's instructions. I use the same ratios for my mix.
Your fish will be fine. I use a 2L bottle on my 10 gallon and there is nothing to worry about. Also are you running a power filter? If so stick the tubing in the intake a little bit and let your power filter be the diffussor. Works well, a lot better than just an airstone.
I have been running a DIY CO2 system for at least 2 years and have not found the need to run an airstone to remove excess CO2 at night. The amount of CO2 that is accumilated during dark hours does not really build up to the point of possible problems with pH.
The best thing to do is to measure the pH during lights on in the morning, if possible mid day then just before lights out. Then just before lights on in the morning take another pH measurement. This will give you a very good idea as to the amount of CO2/pH swing you have in your own set-up.
If the swing is too much then maybe you will need to turn off the CO2 at night.
The best thing to do is to test your own pH/CO2 values in your own tank, because what works for one tank does not mean yours will react the same.
And as for the reason for the baking soda in the mixture is to help prevent molding and bacteria growing in the mix. At least that is what I have read!!!
Either it's bad yeast or you have a leak. To test your yeast get a cup, fill it with semi-warm water, 4 tablespoon of sugar, and 1/4 teaspoon of yeast (this is how i normally reactivate my yeast before pouring it into my mixture). Leave it sitting for a few hours. Usually theres a foam that forms and traps co2 into the water. If you can't really visualize how that looks, take a spoon and stir the mixture. It should sound like co2 is escaping from the mixture. It sounds like you just poured some soda into a cup. If this doesn't happen..you have bad yeast.
Also make sure you aren't adding the yeast to water that is too hot for it. If it's too hot (exact temperature varies with the strain) it will kill the yeast and you'll get nothing. If you put hot water straight from the hot water tap then it would definitely be hot enough to kill it. I'm sure you know this but just thought it might be something to mention.
i used warm tap water. ok, it was making little bubbles and had some white foam with bubbles, but that died down a lot, now its a little bit of white foam, I dont know whats going on. currently testing the yeast and doing what synper told me to do.