Eastland, If your are limited to 1/4 HP and the Gast 0523 rotary is the direction you are leaning this unit will pull about 5.3 amps on 115 volt and produce 3.6 CFM at 10PSI (18-20ft of depth)This unit can be made with the old style Vertex Air 2 or if you have 5.3 amp cap. you could go to a Brookwood piston in an Vertex Air 3 which would give you 4.4 CFM. You are correct in aerating the deep part with your limitations. The important part is to get as much turnover capacity out of you diffusers as these CFM will allow > www.aquaticaeration.com if interested in more details. Good Luck Ted