Great thread...here are some tips I learned on the way.

1.) With a DiY the yeast you use can be based on your tank size. Since you cannot turn off the CO2 at night, you might want one that makes yeast slower/lasts longer for smaller tanks like 10g vs other yeasts that are faster producers for larger tanks.

2.) When first starting, keep the airstone at the surface of the water so that you don't flood it. This will have less water pressure on it so that it can begin producing bubbles faster, then put the stone under and move it down little by little. At some point you may find a depth that is too deep for the airstone and bubbling stops due to the water pressure.

3.) You can also squeeze the bottle a bit to force out the water in the line/airstone once your CO2 begins to work, but wait until you feel some pressure from the bottle or you will be drawing a vacuum and sucking more water back up.

4.) I used to use a 3 way valve in line (no bubble counter) so that if my pH dropped too much or I wanted it "off" at night, I could crack the one valve open and it would leak the CO2 into the air.

5.) Yeast can go bad once a pouch has been open. If you dont get bubbles within 2 hrs, make a new batch with a new pouch. It is probably not a leak.

6.) Keep the bottle at tank height or higher. This helps it overcome the pressure of gravity...and also keeps the water from going in the line once your yeast starts to die out.

7.) Clean the actual diffuser (ceramic, wood, stone) once a week to keep your bubble rate stable.

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--->Pictures of my 75g Amazon tank<----