I'm buliding my own sump, and i'm in the planning phase right now and i ran into a problem. The problem is when the power goes out for whatever reason, that means water keeps on flowing down from my 55 gallon aquarium into the 20 gallon aquarium(sump) and thats bad news, over flow, i plan on put a vaule where I can close it, if this does ever happen which i know it will, but what im afraid of is if i not home and the power goes out. Is there any thing that i can put that will automaticly stop the flow from coming down and flooding my living room.