With a 15'X42" pool, you probably have the cartridge filter. Do yourself, your pool and your bank account a favor. Order 2 or 3 of the good cartridges referenced here.
http://pool9.net/ssr/
Our experience with the Intex filters was not a happy story, and we spent a small fortune replacing them every few days.


Also visit the sister site, PoolSolutions.com for lots more great info.

Enjoy your new pool!

Pappy