well i have a protein skimmer, and the return from one of my tanks is not submerged in the sump so that agitates A LOT of water. and makes a lot of noise. i just dumped a bunch of stress coat in the tank, and doing a 5gal wc. maybe this will help. disconnected heat earlier, and new phs now. need to get a better test meter before i do anything else with stray voltage.