The Rain Harvesting 3″ & 4″ High Flow Flap Valves allow a rapid flow of water through a double sealed, self cleaning valve that cannot be over rotated and left open. High Flow Flap Valves are very popular for installing at the end of your SCH40 Overflow Pipe for mosquito protection. High Flow Flap Valves also prevent pests or birds from traveling up your overflow pipe and finding their way into your rainwater tank, where they usually can’t get out. Vented Flap Valves allow a flow of air over the surface of the water which improves water quality and prevents a vacuum forming when large quantities of water are quickly drawn from the tank/cistern. A vented High Flow Flap Valve is recommended in every application where the overflow pipe is being plumbed on a rainwater tank.
There's no harm in hoping for the best as long as you're prepared for the worst.
- Stephen King