Maybe it's copper poisoning. Get a GOOD copper test kit; sounds like your inverts are all dying but your fish are not affected. That signals trace copper to me. They could also be starving; unlikely, I guess, but I'm sure it does happen.

Also, I don't know about the effectiveness of a 10 gallon water change in a 135 gallon system with 40 gallons of extra water in the sump/refugium. After testing for copper, I'd consider doing a major water change; make sure you test that water for copper too.

I wish I knew more about stray voltage. A volt sounds like it could be a lot to me, but I really don't know. It's a good excuse to chuck the rios over a cliff and write the terrible company that makes that crap a letter. After I got shocked by my rio, and I'm only the millionth person to experience that, I wrote them a not so nice letter asking for my money back. Funny thing, they never replied....