I put valves in all my ponds. I have my 8 inch gate valve open right now on one of my ponds filling a 2 1/2 acrea pond below it. I didnt open one of the valves on one of the ponds for 4 years and now it is stuck. I have had 3 different turtles get hung in the valves when they have been open and had a little problem closing. Had to chop the turtle in half with the valve by opening and closing. I would at least open and close everyk three months for a few minutes. Richey