I am working on a pool that spills over into a catch basin. The pump/filter sit about 70 yards away and at least 45 ft above pool and basin. The customer wants to only run the pump 12 hours a day. There are no check valves near the pool or basin. The bottom drains are 2 inch pipe, does anyone know of check valves that fit in the pipe and allow the covers to go back on?

Wow! Why did they do that? Does it actually run without cavitation? And what happens now when the pump shuts off?

There are three pumps and once there primed they run good but it takes forever to get them primed. They have check valves at the pump but there useless, the pipes are full of air from the check valve to the pool level. The basin had 2 main drains that looked like returns in the floor, so I put inch and a half male adapter and check valve together, sckrewed it in the md's. This held water in the line,the pump was starting great but I went back 2 days later it would not start. I have tested the line it's good, I will work today on this problam if any one has any ideas call me 864-844-1157 thanks

If no air gets in the system why would it drain back, check all connections as air can get sucked in and you won't see water come out.