Ted, I would suggest using 3, 12" diameter pipes instead of small diameter. Use 9" membrane diffusers placed in the deepest possible position with a vertical rise and a long radius elbow to direct your flow. You could put a 2" "vent" at the top of the vertical rise to bleed the air off with minimal flow change. The inlets of all lift pumps can extend into your 3 foot diameter connection pipe.
Last edited by Rainman; 02/04/19 01:08 AM. Reason: Wrong name