With the old docks there was a bunch (30+) gizmos that were hung just off the bottom that circulated the water around all the docks. That worked pretty well but our winter power bills were actually higher than when all the slips were occupied in the summer months. With the new docks we purchased hi volume/low pressure compressors for each dock and run hundreds of feet of copper pipe to bubble all main docks. That really never worked. Most of the other clubs and marinas, including the ones on both sides of our, use anything at all. This is the first year we had such issues with the finger piers sinking. Should be an interesting spring?