Hey Bill, thanks for clarifying that for me. That's exactly the information I was hoping to gather.

My thoughts are to run 1/2" PEX, buried to the full pool line, that run may be 60 feet from the power source, then reduce to the 3/8 sinking line to the center of the pond. The total run of 3/8 should be in the neighborhood of 30 feet, so the relative back pressure should be nill.

The diffuser will be fixed to a platform of milk crates to elevate it from the bottom to a depth of 11 feet. I may go two high on the crates to get it up to 10 feet, and still be light enough to retrieve when need arises.

I'm thinking this should help the pump operate well under it's maximum limits. If 10 feet of depth causes the diffuser to over expand I can take it lower and still be ok.

.10 surface acre pond, 10.5 foot deep. SW LA. The epitome of a mutt pond. BG, LMB, GSF, RES, BH, Warmouth, Longear Sunfish, Gambusia,Mud Minnows, Crappie, and now shiners!!...I subscribe!!