Is this algae?

[Freeflow23]

3 month old NPT Stonescapes pool. Salt. Every so often I get these spots in the deep end. I have an acorn tree (soon to be removed) that drops into this section and I always assumed it was from them. I add the regular weekly muriatic acid and the spots go away. But I don’t think I’ve had this many acorns out there this week. And we just added MA last night but no change. My water stays in this range all the time. My results today do show I need more calcium (even though I’m in the acceptable range). TA stays between 90-100 most days which is borderline.

Could this actually be algae? Can you get algae with chlorine this high all the time? I use my Taylor test kit 3-4 times a week (yes I’m obsessed) and never had anything out of range. I clean my pool twice a day with my vacuum and brush the pool because of the tree mentioned above.

 

[Texas Splash]

If it was algae, you should see movement when brushed unless it was really allowed to set-in and stain. But your pool is so new that wouldn't be my first choice. If those are acorn spots (tannin), then you should see a change with a chlorine product. You could try sprinkling a little cal-hypo on a stained area to see if it lifts it (organic). Which Taylor kit are you using?

 

[Freeflow23]

If it was algae, you should see movement when brushed unless it was really allowed to set-in and stain. But your pool is so new that wouldn't be my first choice. If those are acorn spots (tannin), then you should see a change with a chlorine product. You could try sprinkling a little cal-hypo on a stained area to see if it lifts it (organic). Which Taylor kit are you using?

It does not move when I brush. It usually just disappears after MA is added.

 

[Freeflow23]

This is the kit.

If it was algae, you should see movement when brushed unless it was really allowed to set-in and stain. But your pool is so new that wouldn't be my first choice. If those are acorn spots (tannin), then you should see a change with a chlorine product. You could try sprinkling a little cal-hypo on a stained area to see if it lifts it (organic). Which Taylor kit are you using?

 

[Texas Splash]

It usually just disappears after MA is added.

Acid can impact copper. Do you recall if this started happening shortly after adding the salt? Have any other products other than MA and salt been added to the water? By any chance any fertilizer or lawn products been added recently that may have been blown into the water?

 

[Texas Splash]

Even though you note that MA seemed to help in the past, I would still try two other DIY tests:
- Sprinkle cal-hypo on a couple spots
- Rub them with a Vitamin C tablet

 

[Freeflow23]

Acid can impact copper. Do you recall if this started happening shortly after adding the salt? Have any other products other than MA and salt been added to the water? By any chance any fertilizer or lawn products been added recently that may have been blown into the water?

Ohhhh. My yard guys put out fertilizer earlier this week. We don’t have grass near the pool but it could have easily got into it. How do I fix that?

Otherwise, I’ve only added MA and calcium this week. These spots seem to come and go before and after salt was added.

 

[Texas Splash]

How do I fix that?

Depends on the content of the product used. If it was iron based, you should be able to remove them by rubbing a Vitamin C tablet directly on the stain. Let's hope it's something simple like that for now. Just use the regular Vitamin C tablets you would get at the local drug store. You can rub the tablet directly on the stain, or place several tabs in a thin sock or nylon, crush them up a bit, and rub it that way.

 

[Texas Splash]

If the Vitamin C tablets don't work, the fertilize may have had copper product in it at which point you can try the same test (sock) method, but instead of Vitamin C tablets try some dry acid (aka pH Down).