i think im getting shocked a little. im about to pulll 2 heater out that i addd the other day. i just noticed it after i plumbed in a 20 gallon fuge . before i had a sump and frag tank running and never had a problem. i added fuge and a couple of small heater. i thought i had a small cut but its never bothered me before. it fill like a sharp needle when i tought the water for a second.