I am using a large trashcan as a greywater reservoir using a few bulkhead fittings. I need a valve or float combination that will empty it when full. It needs to hold the drain open until the water level is very low then close again to wait until it fills up (laundry, showers, bathtub etc...) I want to avoid pumps and float switches and use a simple valve but with a long enough float "throw" to work properly. I've never seeen a float valve used to EMPTY or drain a tank\cistern. They always seem to be fill valves.
I don't think a toilet style ballcock will work because the throw is too short and the size is too small. Is there some kind of sliding valve that will work? Thanks!
