I have a problem with my tank over flowing when I forget to turn the water for my RO in the shed off,what happens is my 4040 RO is in my shed and the hose from my resin vessel goes straight into my van tank through a port underneath the back doors,my waste simply goes down the drain just outside my shed door,however if I fit a ball cock to my tank it will close and stop any more water from entering the tank but does the waste still continue as it is not an electrical solenoid I am using and if the waste does continue when the pure water can no longer enter my van tank will it damage my 4040 membrane?