Best way of knowing pool leak

Water was at level. Pool had some patches done before by American Leak company some years back. but after Pool vacuum put on the water level drop like 3/4 of an inch and has stopped there. Is it possible the vac took out some the vinyl patches made by pool vacuum below?. When pool was open 3 weeks ago it was not leaking. What else can it be and how to resolve this issue? The pool filter has some drops of water coming out every 2-3 mins like just a few drops. I believee this few drops would not have cause a 22,000 gal pool drop 3/4 of an inch? Am I correct.

Yes pool vacuums/robots do remove patches if they are getting old but what about plain old evaporation? Have you done a bucket test?

Fill the pool up to the proper level, place a 5 gallon bucket on the step and fill it with water to match the level of the pool. Observe the water level in the bucket compared to the pool. If they both drop at the same rate you are losing water thru evaporation. If the pool level drops more than the bucket level, you have a leak.