Off delay timer for pump

I need to run a pump that is turned on by rising water for 5-10 seconds after the water level has fallen below the level that turned the pump on. The water level switch would only be closed for 5-10 seconds before the level would drop enough to open the switch.This is for a marine application, a bilge pump. The timer needs to be rugged, reliable, and possible to adjust. It may be exposed to voltages over 16V.I could build something to do this, but would rather buy a proven unit.It seems that the DEI 528T might work, but would appreciate any information about alternatives.Thanks in advance.Coleman Blake

why not use an automatic bilge pump?

Sean,Thanks for the reply.I left out most of the details since I didn't want to take up time and space on an automotive list with boat stuff. The highest capacity bilge pumps are the submersible ones that go in the bilge. When they cut off, the water in the outlet hose runs back into the bilge. In my case, this raises the water level enough to cut the pump back on. This would occur with any of the automatic pumps.A check valve should not be used since it will probably fail in the closed position.You also want to prevent stray current corrosion (like to my 100g aluminum diesel tank) by not having anything electrical in the bilge.There is a switch on the market with a builtin, fixed delay. I already have a better switch and need to add the delay.ColemanColeman Blake