Like Rex Rains said on FB, check the CGFI to make sure it's good. I.e. plug something else into it to see if it trips it. If it doesn't, then the ground on the compressor is most likely bad. What age is it? When was it purchased and installed? There should be a label inside the cabinet with a date code on it - 4 number code. first 2 are the month, last 2 are the year. Is it still under warranty?

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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).