Looks like you've done some good work! One thought...If I understand correctly, your system back pressure alone is 1.5 psig and the relief pops at 4 psig. With those numbers you will not be able to place a diffuser in 7ft of water. 1.5 + 3.5 (7ft) = 5. Your relief pops at 4 so the deepest you can go is about 5 feet. Anything you can do to reduce the back pressure? The 100ft of 1/2 inch line is almost no back pressure. I suspect the majority of that 1.5 is coming from the diffusers. Maybe lots more holes in your diffusers?

……..Just a thought

Last edited by Bill D.; 10/26/19 07:10 PM. Reason: clarification
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