Hi Bob, good question. This has been a good thread and the answer to your question sure seems like it belongs here. Always leave between six inches and a foot of water in your pool. The reasons for draining can be many. Usually they are to patch holes or to clean. These can both be done while still leaving six inces of water in the pool.

The only exception to that would be a pool in it's first season that needed work done under the liner. That could be to apply more grass killer, relevel or other such things. This can be easily done in the first season. Beyond that just keep water in it. If the pool is inground with dirt backfilled against it, never drain until you need to change the liner. At that time do the whole thing in a day or two. These pools love to cave in.

Later, Dennis