Did you clean out the impeller? Esp. with hard water, a film build up on the impeller shaft/magnet will slow things down considerably. You can soak the impeller in vinegar (or CLR) to clean ... just rinse well before reuse.
Other places to check: the quick connect block, the connecting hoses, esp. if you have any elbows, and any intake strainer, spraybar, etc. Take the connections apart as much as possible, then clean with a long handled "bottle" brush. <LFS
sells ones with handles that are 2-3' long just for this.> Pay attentions to any elbows or corners, that's where things tend to be stuck.