Look inside the livewell to see if there is an overflow outlet somewhere near the top of the tank. If not, then the plug in the hole at the bottom of the tank should be removed and a "standpipe" installed. If you don't know what a standpipe is, lift the lid on your toilet tank at home. That big pipe in the middle is an overflow that allows excess water to be drained rather than running onto the floor. The standpipe is a plastic pipe with a rubber deal on the end that simply slips into the hole in the tank. It should be cut off about an inch or two shorter than the depth of the tank. YOu then flip the switch and you can leave it on to continually cycle water or shut the switch off. Most newer boats in that class have a livewell timer. It can be set to CONTINUOUS where the pump runs continually, or set to AUTO where the pump runs for a minute or two and is OFF for three or four minutes. Some of them are even adjustable. Simple system.