Well if you'd like some input from the creator of the bubbler...

The original set up goes like this...You use rock wool cubes, place strawberry crates on the bottom of tub, to prop the rock wool cube up higher. One air line (no stone) goes directly under strawberry crate, another air line (no stone) is on the outside of the strawberry crate...water turbulance oxygenates the water.

Although the Cannabis Bible doesn't acredit the bubbler to anyone. All the old timers know it was
Bill Wonder that introduced it at cannabis culture at the begining of the decade.