When I discussed removing the sand with our pool company, they advised against it, saying it's best to just leave it alone until it's time to replace the filter. He said the reason for this is because those filters tend to break when trying to replace the sand, and then you have to replace the filter anyway. He said it wouldn't be necessary to replace the sand if the water was staying clear. Perhaps that's the reason for such a large filter for our pool.
Bookmarks