You don't need the pH to be any higher, what you need to look at is the alkalinity numbers. Those should be over 40. We run in the 180 range up here in Northern Indiana.

For a compressor, you don't need much, 1/4 hp would even be overkill.

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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).