Hello, New to Forum.

[Pappy]

This is what we upgraded to this year. It is much better than the cartridge and a LOT less maintenance.
http://www.intexcorp.com/index.php/h...s/56673eg.html
You can find it on Amazon for much less money than direct from Intex. http://www.poolforum.com/amz/

Intex Sand Filter Pump 2100 GPH

Here's a step by step of our change over.

http://www.poolforum.com/pf2/showthread.php/23562

If you decide to stay with the cartridge, you NEED to get GOOD cartridges (Unicel or Filbur) referenced here.
http://www.poolforum.com/pf2/showthread.php/17055.

Good Luck!
Pappy