For the few hundred bucks, buy a new filter. We are talking a little over $300 for a DE, $250 to $300 for a sand filter (and $20 to $30 for the sand).

Are DE filters better than sand? Well, they filter finer stuff but that doesn't make them better. Sand filters are easier, and with proper routine care, require less maintenance. If you buy a 10 lb box of DE and add between 1/3 of a cup and 1 cup to your skimmer each time you backwash your sand filter, it's performance will jump to rival a DE's without the hassle. And a 10 lb box of DE is dirt cheap (I paid $8 at an expensive pool store) and probably will last you 2 seasons.

I'm biased: I'm on my fourth season with a sand filter-same sand, had a tiny cartridge in an Intex donut and hated it, and my dad had DE for 20 years. I like sand best.