Potential gray mottling in new plaster?

[c_cox]

Hey folks,

My new in-ground pool was finished in late March of this year. The builder used Florida Stucco white (undyed) plaster with Sky Blue gems, and ever since the pool was finished, we've noticed some plaster discoloration that has gradually darkened. Most of the discoloration is in areas where the crew walked on fresh plaster with spiky shoes during the plaster application process.

We had our water tested by a professional lab, and our iron/copper/etc levels are quite low, so it shouldn't be metal staining. Are these stains the gray mottling that sometimes shoes up with incorrect plaster mixing / water use during troweling?

Please note in the pictures there are also some brownish organic stains; those happened when we had leaves fall onto the fresh plaster before the pool was filled. (The pool is surrounded by large trees, and a screen enclosure is in the works.)

Thank you so much for your help!

Current water test results:
FC: 12.5 (I bumped it up temporarily because we just had a big storm and were blessed with a bunch of frog eggs)
pH: 7.5
TA: 90
CH: 375
CYA: 60
Salt: 3200
Temp: 90 degrees F

 

[Texas Splash]

I'll tag @onBalance to see what he thinks.

 

[onBalance]

That gray discoloration in your pool does seem to be the gray mottling that I have written about. However, please run your hand on those areas to see if the plaster finish is smooth and does not have rough calcium carbonate scale deposited on the surface. See below.

How White Pool Plaster Can Turn Gray

One would think that when mixing white cement with white limestone aggregate, the final pool plaster product would always be white. But that is not always the case. Unfortunately, white pool plaster sometimes turns gray (or grey) either immediately or a few months after the pool is filled with...

www.troublefreepool.com

How White Pool Plaster Turns Blotchy

This experiment below explains how white pool plaster can become blotchy gray, and also have white areas mixed into the gray areas. Both white pool plaster coupons below have been in water for one year. Sometimes the water was slightly aggressive (negative CSI), and sometimes the water was...

www.troublefreepool.com

 

[c_cox]

Thank you @Texas Splash and @onBalance ! The plaster finish does feel smooth in the discolored (and non-discolored) areas. My next door neighbor had a pool done by the same builder at the same time as I did, and his plaster has the same discolorations.

Assuming this is the gray mottling - it's primarily an aesthetic issue, correct?

 

[onBalance]

Yes, it's primarily an aesthetic issue. And power-sanding would remove it.

 

[c_cox]

Good to know - thank you again!!!