Sand Filter Does The Sand Ever Need Changed?

[footie]

I have a dosing pump that measures the chemical needs and I use either dry acid or baking powder to control the pH plus all the other water tests that need to be done but I use a large sand based filter with which I do regular backwashes and cleaning cycles but I was wondering if anyone knew whether or not the sand ever needs replacing. The swimming pool has been running for 8 years.

Thanks.

[Pool Clown]

There are some that believe the longer you leave the sand in, the better your filtration, unless of course it begins to channel. I think that it is best to change the sand at some point. At what frequency? I believe that depends on a lot of variables, the most important one being if you want to spend all day scooping sand out of the tank. Replacing the sand does give you the opportunity to open the tank, and inspect things inside.

How's that for an information-less post?