Another thing that I didn't mention is that my overflow outlet it next to the intake draw for the fill, which are both near the bottom of the boat. If my overflow tube is 18" to 2 feet under water, nothing will drain without the boat underway...it will have to be pumped down. If you are constantly adding fresh water setup on a timer, then pull the white recirc pipe and then let it pump it down setup on a timer as well.