New to the neighborhood...

[BSpade]

...
Forgot about the suction leak! Read http://pool9.net/leak-s/

I replaced the section of inlet pipe between where the inlet pipe comes out of the ground with a short curved piece of 1 1/2" Schedule 40 pipe (from the electrical department - wires seem less tolerant of sharp bends than water). With the new pipe I could take advantage of the 1/2 union that came with the pump (the pump inlet is the other half). The old pipe was composed of short pieces of pipe and 45 degree connectors and a 1 1/2" threaded connector and a a 1 1/2" to 2" threaded adapter, and was probably 10-20 years old, and was badly sun damaged, and the threads on the connectors seem to be worn enough that no amount of Teflon tape would keep it from sucking air.

Now, when the pump goes on, any air in the input strainer disappears with seconds, and the only air I see is one small bubble quivering in the handle portion of the clear plastic lid.

And the pool sweep (Polaris 380) seems to be quite happy with the main pump on low speed, so I don't plan to use high speed much.

Thanks for the help.