I was working on the ceph system to get it ready for some CB bangaii's in one of the 'extra' tanks and an on floursecent light on the live food tank fell in the live food tank. My hands were in the water and everything. Click, the GFCI tripped and turned everything off saving not just my live and everything in the systems life, but saved my daughter from watching me be electrocuted. Precautions will be taken to avoid the light being able to fall in the future, but even in the best designed system bad things can happen. Don't take the risk, install a GFCI GFCI = ground fault circuit interrupt, sometimes called a GFI. They are available to replace the receptacle in your wall from you home improvement store (you may want to consult an electrician for this) or are available as a wall 'wart' for about 10 bucks. This one is nice because it will come back on after a power outage - http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=TM-GFI&Category_Code= . On my systems I actually run several so that if something trips, everything doesn't necessarily turn off.