Originally Posted by ThatPlantedTank
Which way should my valve be pointing? And can you give me a rookie mixture for a 30g that won't kill my fish?
You mean the check valve? If it does not have an arrow on it indicating the airflow direction, you could blow into it to see which side has more (or less resistance). Basically, if you can pass air through it, the that is the direction the CO2
should go. Once you figure it out, mark it with a Sharpie marker. If a metal spring is present, then it is usually on the outgoing side of the valve.
Here is the recipe I use for a 20g tank with plants and fish:
Assuming the lid is prepped with the silicone airline tubing or otherwise sealed, I take a 2 qt/liter plastic juice bottle (wide lid easier to work with and wider base less likely to tip over) and fill it about 3/4 with VERY warm water. I add 2 cups of sugar and stir it until dissolved. I then pour about 4-5 oz. into a clean, empty water bottle or a glass. Next, add 1/4 tsp of yeast to the bottle or glass. Cap and shake vigorously or stir until well mixed. Wait about five minutes, remix, and pour this back into the main bottle. Add the cap and wait for the bubbles to form. This mixture lasts 1-2 weeks.