Find what? there's nothing to find, it's low speed, high speeds little brother, any type of diagnostics, measurements (P.S.I.), valve adjustments for suction cleaners, heater operation, spa jets, etc, are done on high speed generally as a rule, looooow speed is for taking it easy, saving a few dollars, just circulating the water, it's not gonna be aggressive and fill the pump basket/lid area to the top with strong flowing water like high speed.
One of the things i like to do when checking out a pool is to run the pump on high, bleed the filter tank of any air, then turn the pump off, air leaks can reveal there location by any bubbles in the pump lid area, like under the lid itself, from the front inlet pipe into the pump, how much the filter tank may bleed down (blub blub..blub blub) does it blow the skimmer deck lid 20' into the air from a strong back flow of water, does it not pick up, or is it slow to prime the next day after sitting off overnight,etc (this is worst case scenario)
Or, after the pump is turned off does it hold a seal, and make no bleed down noise at all, no air bubbles appear under the pump lid, the water stays high up to the pump lid, and it starts up instantly the next day, with no priming delays (this is the best case scenario)
After working on thousands of pools over the years, i would say the time to really be concerned about air leaks would be if the pump no longer has the ability to prime on its own anymore, or if it takes a very long time to pick up prime, ( the garden hose pump basket filler people out there, you know who you are)
So...does your system hold a reasonably good seal? does it prime quickly? if so, don't become obsessed with an air leak witch hunt.
