I have a KoolWell system in my boat that takes care of the catch by circulating the livewell water thru the cooler via hose's and a small radiator and an extra pump. You can set the thermistate to about 8 degrees below lake temp while running your livewell on recirculate. I still change the water out at least once a day sometimes more depending on how many fish. I also add 1/3 cup of uniodized salt for each 5 gallons of water and 1 capful of rejuvinade for each 20 gallons of water first in the morning then again at each water change. The fish are in top condition even if its a 100 degrees outside. If you need anymore info on this system please send me an IM. Her is a good link to read [URL="http://assets.espn.go.com/winnercomm/outdoors/bassmaster/pdf/Keeping_Bass_Alive.pdf"]