I had ordered two of these check valves several months ago and not installed them because I was planning on being farther along with my basement sump and didn't want to waste the valve once it was plumped. Well two power outages since then I have changed my mind. My sump is not quite big enough to hold the water from the tank and I loose about 10 gallons each time it happens. Once while the power was out I was on the phone with case and AP&L tuned the power on and off three times, it was like I was a puppet and they were pulling my strings. I never was able to stop the cavitation of the flapper type check valve that is primarily offered by fish stores. This is a positive pressure valve meaning that the valve is forced open by the flow through the valve from the pump and not by the back flow of water when power is turned off. It does cut down on the flow rate some but this will be only a clam tank when all is said and done.
