diy ph controller problems
I am building arduino based ph controller but I have problems getting stable readings. When I tested ph in plastic jar readings ware stable, but when placed in aquarium ph was all over.
After some google consulting I realized that the problem might be ground loop. I measured voltage between aquarium water and ground and it was 2.2V ac, current was 0 mA ...uh
I then changed my power supply for arduino from switching to transformer to achieve galvanic isolation and that worked ...until lights came on. I have Juwel T5HO 2x54W.
Should I ground aquarium water? Any other idea?