ok well i have decided that since there is becoming a noticeable difference in my planted tank from one side of my tank where the store bought co2 system is to the other end so i decided to run a 2 liter bottle with a hole drilled in the top with an air line running to a shortend uptube for undergravel filters and a simple airstone with me adding a check valve os that way i can control how much goes into the tank. well today is day one of the trial it seems to work like it should since the co2 bubbles up to the top and most of it stays there for a bit then goes up the tank.

I HAVE A PRETTY SUCCESFUL DIY co2 diffuser on my planted oscar tank