Yellow "sand" on walls of pool

[Lee J]

I'm opening the pool and have gotten all the gunk out of the bottom. I have a yellow grit on all the walls of my pool. I have tried to scrub this stuff off but I think it's on there with super glue! Any ideas? I can add pictures if I need to.

 

[Richard320]

Gritty tends to point to calcium scale. It can very easily get algae or iron embedded in it as it forms.

Pictures will help a lot. So will test results.

 

[BoDarville]

Lee J

Welcome to TFP

Pics would certainly help. Here are a couple of suggestions:

• 1. If you have a trichlor tab, rub that on part of the stain. If it fades, then it is organic in nature (in your case, it could be mustard algae based on your description).
  2. If you have a Vitamin C tablet, rub that on part of the stain. If it fades, then it is a metal stain. If the Vitamin C is in an enclosed capsule, you would need to break the capsule open so that the actual Vitamin C gets in contact with the stain. A tablet form of Vitamin C is best to use.

Either type of stain can also be embedded in calcium scale as Richard320 has pointed out.