I'd move the white one to the tip or the center of the 12' deep area closest to the spillway, and move the black one much closer to the upper tip of the 8' deep area nearest the top spring side of the pond. Then sue the ball valves to equal out the boil coming to the surface from the two diffusers.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).