DE Replacement

[mshumack]

PatL34 - while that method may work for you it uses a hell of a lot of water. I have a DE60 and find it much more cost effective to open it and hose it down rather than backwashing it.

I agree, it is better to disassemble, clean, then recharge with the full amount of DE.
When I first got my new pool running I did the backwashing method to clean the plaster dust and it would drop the pool water about 2 inches (in a 20,000 gallon pool). The pressure would return to normal but raise again realitively quickly (days). A few weeks later I disassembled the filter and discovered that a huge mass of DE and old plaster dust cacked at the bottom. Now I only disassemble to clean. It doesn't take that long and I know exactly how much DE to add afterwards.

P.S. I have the Pentair FNS Plus (60 sq-ft) and it takes 6 lbs DE when empty. If you have the 48 sq-ft model you shoul donly be adding 4.8lbs. If you have another brand, check your manual.
Good Luck

[PatL34]

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