I agree...plan on leaving diffuser in deep part till its non functioning....don't need to repeat the clown fest with weighted hose etc, paddle boat and canoe....any way plan on building a 2 valve Assembly...turn off deep one turn on shallow one....with 3'- 4 feet of snow on ice....I don't know if a single regular diffuser shallow will provide enough oxygen...I saw briefly...somewhere...a slit weighted hose...for shallow aeration...any one have any idea or experience with something like this? Wide open to home made devices as well.....speaking of home made was thinking of using a couple of gate valves to control which hose gets air....another topic perhaps.

Dick....Offer a sincere thank you to someone today. You just made the world a better place.....unless you teach someone to fly fish...then you really make a difference!