HELP! Nitrate spike - things going down fast :(

[Jessie]

Okay, so I think I figured things out...
I was electrocuting the tank :0 I heard this clicking sound (like a static spark), very randomly and not overly often last night, and upon further inspection today, I moved a couple power lines (Hydor heater line and Hydor powerhead) and heard the click again. I unplugged and removed both items and all of a sudden my clowns are swimming around like they use to and Blenny seems a bit better. Thinking the "sting" on my arm isn't from the corals...also, I do have a Hydor nano slim skim (doesn't work very well, still oily on top of water). Well I hope I have figured out the problem for sure -still going to do a 50% water change for Nitrate sake. Thanks everyone for your expertise, it is so much appreciated!