I can understand that with a 60 sq. ft. filter the need to backwash is not that high.

The fact that when you open up and find lots of DE caked in the bottom indicates that the flow is inadequate to backwash properly. With the 36 sq. ft. that I use, I can backwash in 5 minutes or less, and have 4 lbs DE added in less than a minute.

An hour before I wrote this post, I had to open up the filter, disassemble the grids and wash them because I could not backwash normally as the city was doing storm drain work in the street. There was a small amount of caked DE in the bottom but nothing more than usual, and I have just had the pool replastered.

The point I am making is that I barely use more than 100 gallons, if that, for the whole backwash process. To me a 60 sq. ft. filter is much bigger than I would ever need.

Pat