outsider:
You need an isolation transformer for the pumps, 120 to 120VAC and 300 VA (VoltAmps) per pump, I believe current leaking from a pump and going to ground through the water is causing your problem.
me too but im trying to imagine not such an expensive and bulky task becasue it just wouldnt be worth it. i could get a commercial monitor for 700$ probably the same price as an isolation transformer of that size. can anybody tell me if this will work. https://www.dfrobot.com/product-1621.html to eliminate the ground loop problem im having. i could power the entire ph circuit with this maybe . possibly even a low pass filter on top of that