Mel,
In the old days recommending a 3 HP pump for your pool, would not be good advice..
The good news is we no longer live in old days...
Today we have Variable Speed pumps.. Actually they really are variable HP pumps.. This allows you to have plenty of HP when you need it, and very little HP when you don't.
This is why the 3 HP IntelliFlo3 pump that Allen recommended makes so much sense..
The bigger the pump, the more water it will move at lower speeds.. the lower the speed, the less it costs and the quieter it is..
I have an older 3 HP IntelliFlo on my simple pool which runs 24/7, mostly at 1200 rpm.. The cost to do that is less than $20 bucks a
month. It is so quiet, that you almost have to touch the pump just to make sure it is still running.
Thanks,
Jim R.