Quote Originally Posted by waterbear
Probably the WORST filter you can get is an UNDERSIZED cart for you pool. Oversize it a bit.

Evan is wrong. The worst filter you can get is an undersized filter of ANY type, Cart, DE or Sand!

If you want the easiest filter to maintain then you want sand. It filters to about 60 microns which really isn't that shabby and backwashing works well with a sand filter. They still should be broken down about once a year and the sand cleaned and checked for channeling.

If you oversize your sand filter and are happy with the performance, this isn't necessary. I would disagree here and say do NOT do this unless you have a problem. Even more, the dirtier the sand is over the years, the finer it will filter--it gets BETTER with age!

In actual practice you wll be happy with any filter you pick..All three types do a good job with different tradeoffs. You just have to decide which one is right for you!
Gee--I thought I said that!

Unfortunately, we don't yet know of any research on the improvement due to adding a little DE to a sand filter. Everyone who has used it has been THRILLED with the results (including me). At night, you easily far less stuff in the water when the underwater lights are on--I'm simply amazed at how clear it now is. All the ease of sand filters, and, apparently, most of the performance of DE filters!

Ah, but if only someone would do some research on the filtering increase...You use FAR less DE in the sand system than you do in the DE. I only backwash every 2 or 3 weeks, and only use about 3/4 of a cup of DE each time--that's about 1/4 to 1/3 of one of those large DE measuring cups!