Can find cause of all the dirt/sand in the pool

[matt4x4]

Nicole - that MAY have been your problem all along, that the old gasket was MISSING a web - therefore, sand can blow by.
If this gasket IS in fact for your filter, then maybe teh old gasket was not the right onr or a piece broke out - did you inspect the old to see if a piece may have been there before (little rough spots or something where it should be connected to the inner/outer rings)?

Edit - I just went to astral and checked into it, probably is the wrong part, don't know since I don't know hte exact filter you have......
Here's a link to look for yourself - it looks like the ones with the one less web also have a bigger center ring - just like yours.
Maybe you can find the right one and order it directly.
http://www.astralpoolcatalog.com/Hom...esidential.htm Choose filter from there...

If you have the Millenium or Cantabric top mounted 16/20/24" model (likely you do), then it's the wrong part, you need part number 19028R0204, what you got was for the side mount 30 or 36" Aster or Cantabric part number 07441R0002