What is it?

[CanuckPool]

maybe its acid rain!!!!

[Simmons99]

Acid rain just has a PH below 7.0 - I don't think that would make it black - muriatic acid isn't black.

Probably stuff that washed into the pool during the heavy rain. We get a lot of sand from our paver deck into the pool when we get a heavy rain.

[waste]

Any chance you have a new 'stamped concrete' deck ...?

[CanuckPool]

hey waste, you're good!! I do have a brand new stamped concrete deck. Could it be the rain washing some of the dark accent powder along with some of the sealant into the pool. It only seemed to happen that one day of really heavy heavy rain, and it wasnt really that much muck.

[waste]

Not so sure about 'good', just concious . In the course of my work I see the same stuff in almost every pool with a 'stamped' deck, hope this puts your mind to rest on the 'stuff'.

[CanuckPool]

I thought I had another exxon valdez on my hands

[smallpooldad]

Lived in Central Los Angeles for three years.

The pollution settled onto the pool daily. This is potentially what it might be - soot.

We used to scrub it out.

Aloha