AF, I think you should run your deeper diffuser at least 30 minutes a day to start and double the run time each consecutive day to make the deeper water available to your fish. With your diffuser in the shallower area and the big pump churning the top, you will be pretty safe and degassing your anoxic water that will be lifted. I think you will stop smelling the sulfides (the stench) pretty quickly. Once you don't detect any odor in the deep water boil, you should be good to run it full time.
