(Click on the above image for a larger view)
I built this
air stone manifold to get rid of all of the little airline tees in a multi
I took a 1" PVC coupling and glued a 1" PVC plug in one end
and a 1" slip x 1/2" FNPT bushing in the other end.
I drilled four 11/32" holes around the bottom edge of the coupling
and tapped them with an 1/8" MNPT tap.
I screwed four 1/8" MNPT x hose barb elbows in these holes and a
1/2" MNPT x 3/16 hose barb in the top.
Install your airstones with short pieces of airline and you are ready
I got the hose barb fittings, tap and drill from www.aquaticeco.com