Quote Originally Posted by jtcaputo View Post
I had assumed it was just a matter of impeller rpm.
All induction pool motors spin at around 3450 RPM on full speed. A two speed motor will spin at 1725 RPM on low speed. A pump's head curve is determined by the impeller so a larger pump will have a larger impeller. Either in diameter, width or both. However, increasing the size of the impeller increases the load on the motor which is why a larger motor is needed too.

But back to your problem. This is basically one of the downsides of a suction cleaner. Some cleaners will work with less flow rate such as ThePoolCleaner so that is another option. Also, you could automate the valve so part of the run time is on the cleaner and part is on the skimmer.

But up sizing the motor generally doesn't get you much. Maybe 5% additional flow rate for each 1/2 HP. But that extra 5% in flow rate costs you an extra 20% in energy. I would focus on another solution such as the valve automation.