I tried to post a new thread about this but was blocked. After draining the pool, I discovered it is 12 feet deep! Much deeper than the 8 feet I thought it was. And the shallow end is 4 feet, giving me a total volume of 33, 510 gallons. Oy, the water bill! Almost double what I originally figured. This seems unusually deep. There used to be a diving board so I guess it makes sense and I suppose they used to dig pools deeper than they do today. The house was built in '55 and I don't know the age of the pool. My learning curve keeps getting more steep.