White dots that look like Black Algae but are white

[09659]

I saw a pool today that had white dots that look like black algae but are white.

The plaster is black.

The patches of dots are in a couple of patches on the floor.

What caused these dots? Bad plaster mix?

Thanks

 

[jblizzle]

Calcium scaling? You want us to guess with no pictures or more info?

 

[09659]

It's hard to take a photo of it where it's at. It's looks just like black algae but it's light grey / white.

 

[09659]

They are dime sized dots.

I was told that vigorous brushing with a stainless steel brush had no effect.

 

[jblizzle]

Maybe someone threw some granulated chemical in and it faded the plaster?

 

[09659]

Are they bleached black algae spots?

 

[Melt In The Sun]

could be, but a brush should remove those easily. They do bleach gray/white.

 

[onBalance]

You might consider that they are either calcium nodules which begin as white bumps or mounds and then turn brown over time http://www.troublefreepool.com/threads/66499-Calcium-Nodules-in-Pools

Or White spots that are very smooth on the surface http://www.troublefreepool.com/threads/54515-White-Spotting-of-New-Plaster-Pools And http://www.troublefreepool.com/threads/55709-Scientific-Evidence-on-Plaster-Spotting

White spots can occur on white plaster or black plaster.

 

[09659]

This is it!

Defective plaster.

Thank you!

 

[onBalance]

Here is a photo with white spots on a black plaster pool.