The optimum range is 50-200, but I'd like to see it closer to 100+ than under that. The higher it is, the less the pH will swing during the day too. High swings put more stress on the fish.

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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).