Fine dirt on pool bottom that clouds when vacuuming


New member
May 12, 2019
West Virginia
We just opened our pool for the year (we moved here last year and pool
Was open already) there is a fine dirt substance on the bottom that clouds when vacuuming. We’ve had a TON of pollen here this year and my husband thinks it’s settled 100912 on the bottom. The water is crystal clear but we can’t seem to keep the dirt off the bottom. I attached image. I don’t think it’s any kind of algae and it clouds up super easy with no scrubbing just so fine it settles back down.


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
If it behaves like aquatic dust bunnies, it's algae.

I suspect that if you sneak up on it with the vacuum it will get pulled in rather than pushed away by the wave being displaced by the vacuum. And then SLAM Process it. Eradicate it now and enjoy the rest of the swim season or fight it for months. Your choice.


New member
May 12, 2019
West Virginia
Welcome to the forum!
Classic sign of algae, most of it is dead, but you should do a SLAM Process to eradicate it completely.
Let us know if your interested in that and we can guide you through it. You do need a proper test kit to perform the SLAM.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
Do we need to somehow get all of it off the pool bottom before the slam? That’s the issue we are struggling most with is getting it vacuumed up


Gold Supporter
Sep 19, 2016
If it's algae (and it likely is), as you're slamming, you'll kill more (and subsequently make more of it in the bottom of your pool). So there's no reason to wait to slam until you have it cleaned, because as soon as it's cleaned, there will be more created when your FC attacks it...


Active member
Sep 14, 2015
Azusa, CA
Hmm. I've personally had issue with this in the past and have seen numerous posts here about the same problem. I'm using proper sand and actually have taken my sand filter apart in the past because I was worried about a cracked lateral or channelling... everything looked fine. Adding a little DE and/or vacuuming to waste were there only things that helped.