Having gotten 7 inches of rain in January, the pool was in serious need of a good pumping out. So I put the spare pump on the top step of the pool, ran the outflow hose into the patio sump (which pumps water out to the flood control chanel), plugged it in, and walked away. A few hours later I unplugged it and went to bed.
The next morning, this was the water level. Notice where the leaf is floating. That's six inches below where it had been the prior afternoon. And this is the lower end of the pool (the deep end of our pool is higher out of the ground than the shallow end, but that tilt hasn't changed in decades so no worries). The deep end, where the filter pump inflow is located, was high and sadly dry, and not able to maintain suction for filtration.