Stray voltage

[iceman86]

Originally Posted by GoFish

What would be causing it? Perhaps everything
Could be "Magnetic induction" Had noticed the same issue in 2014 and discussed it HERE. Gets complicated. I no longer test for stray voltage, probably should but still don't know what to do about it

Lots of good info on that link but it's not stray or induced voltage from the pumps because they were all unplugged when I tested.

I don't think the voltage is enough to harm anything but I need that ph probe to stay calibrated and working properly to control my calcium reactor. I'm not sure if it's because the controller plug in only has 2 prongs but from the googling I've done it looks like that's the right plug in.

Another strange thing I noticed is when I hook up my laptop to the controller while everything was plugged in, the voltage dropped to 2 volts. That was with the laptop charger plugged into the laptop. If I unplug the laptop charger it's jumps back up to 20. Could it be because the laptop being connected to the controller has a 3 prong plug in and takes the voltage from the controller?