[djscal]

I've read that it is important to fill the tub periodically with cold water, add a teaspoon of bleach and turn on the jets. Then drain and refill the tub with cold water (no bleach) and turn on the jets again to flush out the bleach. The good thing about bleach is that it kills almost everything, the bad is that it smells really bad!

The problem is of course that no one will remember to do this.

I'm sticking to chemically treated hot tubs myself.