ok. i was just thinking since traces of algae may be left in sand i would change sand out.

well, since last post pool floor still looks good.

the only thing is that when i brush the floor, plastic brush or wire brush, this stuff still there. not as noticeable anymore. not as thick or brown. but a thin pale cloud still there when i brush. had 20ppm of clorine constantly at least since may 10th. what else could this stuff be:

my pool is plaster- could this stuff be residue from the plaster like if plaster was wearing away?
could it be residue from all the tri-clor ganules i've been putting in?
could it be pollen?
again, this stuff is not in patches or some here and some there. it is evenly distributed throughout the whole pool flooor and walls.
i have nothing covering my pool. its opened to the environment. should i just assume that i'm always gone have something on my pool floor whenever i brush, like dust/silth and it's never going to be completely clean?

assuming this stuff is algae, and it's dead, if i throw in some algae preventer will it still work?

how can i know what this stuff is? i have made some progress thanks to this forum's advice. just wish i could get rid if this stuff completely so that i know my children will be safe going in.

ps- the distilled water i've been using to do the shotglass cl measurement has fluoride in it. would this throw off the readings?