When they poured gunite in my pool, I asked the builder about water pooling at the bottom from all the watering. I was told that it is okay and in fact good for the water to pool at the bottom. Sure enough, it pooled about 1.5 feet deep at the end of the 10 days. It wasn't until about 1.5 months later, when they completed all the stone/concrete work, that they drained the water.