New to this page, needing some help identifying and removing this stain.

mic559

New member
Mar 12, 2025
4
Modesto, Ca
Pool Size
26000
Surface
Plaster
Chlorine
Liquid Chlorine
Hello, located in Modesto, CA. I have a 26,000g diamond cut plaster pool and noticed these areas wouldn’t come off when I brushed it. Took a water sample to local shop they said no iron, copper or Algae but CH and PH was high so I’ve been adding Muriatic acid to bring it down. They couldn’t identify the stain though. Any help would be appreciated.
 

Attachments

  • IMG_7954.jpeg
    IMG_7954.jpeg
    369.2 KB · Views: 21
  • IMG_7977.jpeg
    IMG_7977.jpeg
    318.5 KB · Views: 21
is better than asking a pool shop.

 
Hello, so based on the test results it’s not a metal stain. A plaster guy said it’s calcium scale. Any recommendations on how to get it off without draining? Other than the spa the area that is affected in the pool is in the middle of the pool so not very easy to get to without climbing in unless using the pole. I’ve gotten the PH down to 7.2 hoping that it will start going away but it’s been about 3 days of that and brushing with little difference.
 
Here is an article to start with

Did you use the Jacks Magic Stain ID kit?
Sorry, I thought I responded to this. Yes I did use Jacks stain kit and found the #2 to show the most reaction. I’ve already had the water tested for copper and it was 0 nor do the stains have a copper stain look to them based on the pictures I’ve seen, so must be the scale. I’ve looked at the Jacks stain treatment # 2 but keep seeing mixed reviews as to whether it is worth the high price tag.
 
If scale the best way to remove is to polish the pool surface. Though it is very labor intensive, and the pool must be drained.