stray voltage, how much is ok?

Way to much you have a leak somewhere. I usually say anything above 2mv, is a leak. It is best if there is no stray voltage.

Florescent ballast will cause interference with voltmeter readings so to get a good reading turn off the lights, and use the ground on an outlet as the base.
 
First make sure that any salt creep is cleaned up and re-measure. The second thing I'd check is for calcium buildup (I drip kalk and get calcium buildup in the pumps/powerheads over time).

Also, I have found that stray voltage can be very helpful in helping you locate any small hidden cuts on hands. :D
 
Back
Top