Ya'll close off your livewells. Dump a couple gallons of water in each one. Go to Wally world, spend $4 on a gallon of RV antifreeze.
Dump that in the livewells also.
Pump, circulate, move valves, and run all your switches.
Then drain. Then close em back off until the next tournament.
Next time you hit the lake for tournament. Just run the pumps a few minutes while warming up boat.
Nothing will be frozen, broken, or not working.
Nothing worse than holding a 7lb fish and looking a dry livewell.