Quote Originally Posted by fcfrey View Post
If you are using Calcium Hypochlorite (HTH, etc) You will see the calcium which has precipitated out of the CalHypo.

I'm not using Cal-Hypo. I notice this 'dust' when brushing mostly if we haven't been in the pool for a day.

The bottom and sides of the pool feels clean. I mean, when I slide my feet and hands over it it's, like, squeaky clean, not slick or grainy or anything like that. I've concluded it's dead algae bodies which hadn't been circulated enough to be filtered out. Certainly the water has that crisp sparkle which tphaggerty defined.