It is a livewell, my Dad(also Jerry) has the same boat, you should have a switch to fill and empty, its just a paddle to empty, it runs out when you drive, or when you pull the boat out..........where that pic from? It looks like the same swim hole we hit on the Thousand islands
Use Manual Mode to get the livewell full first. Then can switch to Auto Mode. This will turn on the livewell pump for 1 minute, adding fresh water and off for 3 minutes. Take the tube out and the livewell will empty when you take the boat out of the water.
Shoot Mike, I was hoping I had missed a live well on mine because those two rear wells are so tiny they are for minnows only I think or one fish at a time.