The other day, in PetSmart, I found 3 different sizes of bubble disks available. They are not the same brand - (Tetrafin or something - the lower end - but they look good and solid and reliable!) but I am happy.
I am now glueing stones in a "fort" type shape - a circle that will go over the bubble disk. When done, the bubbles will come up from a circle of stones that have plants incorporated in them. IT will be easy to clean (just pick it up) and loads of fun bubbles for the fish to play in.
I got the 6 inch disk for my "big guy" tank - that way there are enough bubbles to lift even the most massive of fishes. Now Rocky can play in bubbles, too!
(THe 6 inch disk needs an entire half of the new blue larger Whisper air pump to power it, though. THere is a lot of area there!)