dumb question

[RavenNS]

I agree, strongly consider using Zeobrite.
filters better,you use less of it, lasts years longer, & you can grow plants in it when you're done using it as filtering material.

Contact any pool store & compare sand to Zeobrite ( or other zeo product)

[tenax]

there's more info at zeobrite.com, but here's the basic skinny on it:

Zeobrite®
Pool Filter Media

The Ultimate Media for Sand Filters:
Provides Superior Water Clarity
Lowers Total Operating Cost
Cuts Backwashing up to 50%
Reduces Chloramines, Odor and Eye Burning
Filters Particles Down to 3 Microns
Environmentally Safe, All Natural
Replaces The Sand In Your Sand Filter
Keeps Your Pool Sparkling Clear, Naturally
Saves Water, Energy, Labor and Chemicals
Easy To Install, Works In All Sand Filters

ps- i've had to do some pretty severe vacuuming jobs lately and unlike sand, i have yet to need to do any backwashing...so i didn't before, but now i do, buy the reduced backwashing capability.