I pulled the controller off the tank and tested it in a pale of fresh salt water away from the tank and using different plug ins. when nothing is connected to the water it reads 2.5 volts. when i hook up the controller with only the temp probe it reads 3 volts. When i hook up the ph probe it jumps to 55 volts.
I also tried the ph probe on the conductivity and redox plug ins and still got 55 volts.
maybe its time to switch to apex
