have been using DIY for awhile.
IMHO, use an injector when you can affort it... much more satisfaction!

also, use a check-valve on the tubing for your DIY CO2 to prevent backflow and suction of all the fermented water into the tank.

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My 90G Planted Tank
18 Yamatos, 6 Rummy Nose Tetras, 6 Pengiun Tetras,
Hairgrass, Hygrophilia, Cabomba