Dirt on bottom of pool

[sbaker225]

We have vacuumed and vacuumed, still after a few hours patches of black dirt is on the bottom of half the pool. It does not puff up like algae and the water is clear as a bell.

Free 3
CC 0
PH 7 ( I know this is low)
Alk 90

Any ideas!!
Thanks for your help!

[Watermom]

When you vacuum, does it initially look clean and then a little later reappear? If so, it may just be dirt. When you vacuum, if you don't move the vac extremely slow, some of the dirt gets kicked up into the suspension of the water. Then, when the water quiets down, the debris falls back to the floor. I see this same thing sometimes in my pool if I get in too big of a rush when I am vacuuming.

Welcome to the Pool Forum and thanks for the subscription, by the way!

[nefretrameses]

I had "sand" in the bottom of my gunite pool. Turns out that low Ph from using tri-chlor tabs exclusively was etching my finish. One year later, I still have a small amount of sand, but it has definitely improved with proper chemical balance. If your pool is gunite, I would get my Ph corrected ASAP.