Welcome to TFP!!!
If the SWG is generating (and I see no reason it would not be), then the pump is big enough (although from what you wrote we still have no idea which size of the Optiflo you have ... add the filter size too).
The pool size and SWG really have nothing to do with pump sizing.
Side note, your SWG is really barely large enough to handle your pool. We recommend sizing for 1.5-3 times the volume of your pool. So the 25k size would be better.