I was just checking my tanks for salinty, and using my finger to drip water on the refractometer. When I stuck my hand in my 20 I got the **** shocked out of me. I unplugged the heater and all the Koralias (there are two #1 and a nano) and then plugged and unplugged the Koralias in one at a time. Each one delivered a mild shock... combined produced a larger shock. So I just removed all of them and replaced with spare pumps/heater. Anybody else have problems with their Koralias causing shocks. I'm just surprised all three of them causing issues at the same time. I clean them pretty regularly, too, in a mild vinegar/water solution.