I think I already know the answer to this. I have an above ground pool. In Texas we have been getting a little rain lately (last weekend was 10") the skies opened up again last night. Lots of pumping water to waste (sorry California if I could get it to you I would). This morning I am standing in the rain pumping again. I get to a level I like and I shut the pump down. I leave the valve set to waste. I go back inside and get back to work. I walk by the back door and see that the pool is an inch or so lower. Pump is not running.
Here is the question. If the valve is open to waste. Will gravity continue to flow the water out of the pool? The answer has got to be yes or I have in the last hour created a monster leak. Learned something new today. I went out and put the valve back to filter position. It started raining again so I am sure my fill is taken care of by nature. Writing a note to pick up some stabilizer.