The DC motor pump above requires no innverter it can run directly off the solar panel power...two basic models available approx. 1 and 1.5 HP (2 HP special order) the 1 HP requires 3 panels the 1.5 HP requires 6 panels custom sizing available qualifies for 30% federal tax credit on total cost of installation. I will be installing these locally call for quote. Pump curves of 1 and 1.5 HP and specs of 1.5 HP below
I was thinking that on lower horsepower motors, panels with built in inverters could be used on your existing pump for a much lower price as long as voltage stays at 115 volts (on 230 voltage it would require two strings of panels which would negate the cost savings of not buying a DC pump).
These pool pump systems are DC solar powered and come with a controller and usually panels too. I saw the pump pictured below at a pool show and they were running pump with just two solar panels and it was a cloudy,overcast day. This particular pump is roughly equivalent to 3/4 HP and can pump about 60 GPM on the average pool on a sunny day. Higher output pumps that require more panels are available for commercial/large swimming pools.
The controller coverts the DC to three phase to run motor.
Link for solar pump website: