What are the correct amount of bubbles the should be exerted from my Powerhead filters? I have the speed set at about 75%. Enough so the water is circulating. 72 gallon bowed front tank. I can turn a little nob on the top, which makes air bubbles. But how much is good/bad? Should there be no bubbles, or some?

Any suggestions?
Do I need to have them both at all?

I don't think you can have too much bubbles. The more bubbles means the more you are air-rating the water, making the fish more active. I have 2 Powerhead 402 in my tank and have them on full blast, and I only have a 55 gal tank. My fish seem to love it, its a form of exercise for them.

You have an undergravel filter with a powerhead on each one? How big is your tank and what kind of fish do you have?

Do you have another filter as well?

Most fish love curent as if gives them something to play/exercise in. Some fish with overly large fins can get exausted with too much though.

No under gravel. External canister and two Powerhead 402 at the top of the tank.
72 gallon bowed front.

Ive got six plants, but I am a amatuer at them. Could not tell you what they are.

Right now only have 1 5" kissing gourami, 2 2" serpae tetra, 1 small frog, 1 betta.

Yes the powerheads have a white sponge.

Thanks! I was wondering if I needed to step up the filtration size/type.

Thanks for the help!