Talk to me about stray currents in the tank

So lately I've been having hell with hair algae and different kinds of algae. I figured something died in my tank and it is causing an issue. No biggie, threw in some phosphate remover, upped the water change intervals, etc.

Then I've noticed that all of my corals have been absolutely pissed lately, which I thought was weird. Even when phosphates are a little too high corals tend to still be ok....

Then today I started to really notice something. It stung whenever my finger was right at surface level. That pain I normally would just write it off as salt getting in to some stupid nick I have in my finger, but this was different. I called my wife over and said, put your finger right here at surface level. Do you feel anything? Tell me I'm crazy. After a minute she started looking at me like WTF is wrong with you? then she jumped and felt it.

That's when I knew the feeling was a stray voltage. I was able to isolate it to a single power head and removed it out of my tank...

Now, that has me thinking a lot of these things are related and I was wondering what all the side effects to stray voltage in the tank could cause? Could it be leaching phosphates that are causing the algae that I'm slowly removing? I'm assuming it is behind my corals being so angry? Any one else know what this crap could have caused?