What are the cause of these stains & how do I get rid of them? - Need recommendations

[Kcdc42]

What are the cause of these stains & how do I get rid of them? - Need recommendations

In the last month or so, I am noticing these stains in my gunite/concrete pool. They are more prominent in the corners (the angled area around the pool floor - where the wall meets the floor. The stains look brownish and dirt like (almost like dirt particles stuck on the concrete). I tried scrubbing them with a brush but they don't come off. Water test does not show any metal presence. Chemical balance looks good (except chlorine is a little high).

I have attached pics below.

What causes these stains and what can I try to get rid of them?

 

[pooldv]

Re: What are the cause of these stains & how do I get rid of them? - Need recommendat

Post a full set of test results. A couple of months worth if you have them. And tell us what test kit you used to obtain them.

Are they rough? Raised above the plaster surface?

 

[Kcdc42]

Re: What are the cause of these stains & how do I get rid of them? - Need recommendat

Post a full set of test results. A couple of months worth if you have them. And tell us what test kit you used to obtain them.

Are they rough? Raised above the plaster surface?

Hi there, here you go. Here are the results from last weekend. I did my test at the pool store.

About the stains, they don't seem rough or raised. Almost like dirt that is stuck.

 

[YippeeSkippy]

Re: What are the cause of these stains & how do I get rid of them? - Need recommendat

What products have you put in your water? Any copper containing algaecides or any product that says "Blu/Blue" on the label?

 

[pooldv]

Re: What are the cause of these stains & how do I get rid of them? - Need recommendat

Rub a Vit C tablet on the stains to see if it lightens them.

 

[63john]

Re: What are the cause of these stains & how do I get rid of them? - Need recommendat

are the Vitamin C tablets available at say Walmart or do need order online ?

 

[YippeeSkippy]

Re: What are the cause of these stains & how do I get rid of them? - Need recommendat

Just cheap-o chewable vitamin c tabs from the drug store or walmart.

 

[Kcdc42]

Re: What are the cause of these stains & how do I get rid of them? - Need recommendat

What products have you put in your water? Any copper containing algaecides or any product that says "Blu/Blue" on the label?

I have only been using the following chemicals this year. None of them says Blu/Blue on the label.

- Natural Chemistry Pool Perfect Plus Phos-Free (2 caps into the skimmer once a week)
- Pool Shock (as needed). This brand: Pool Shock Chemicals - In The Swim
- I also have a Chlorinatior which holds 3" Chlorine tabs. I use this brand: 3 Inch Super Multi-Tabs - 5 In 1 Pool Tablets - In the Swim

 

[basod]

Re: What are the cause of these stains & how do I get rid of them? - Need recommendat

Your CYA is off the charts high so STOP using 3" chlorinating pucks.
Your Calcium Hardness is probably over range high for their test from using the Cal-hypo shock - stop using it as well. Get some bleach(not splashless or easy pour) just regular bleach and use it to chlorinate going forward. Read the articles in Pool School at the top of the page on CYA/CL relationship and use the pool math tool to calculate bleach addition.

As for the stains try a regular vitamin C tablet from the supplements aisle at wally world - hard tablets not gummies

 

[Bobbyj]

Re: What are the cause of these stains & how do I get rid of them? - Need recommendat

you need to get rid of at least half of your CYA so the chlorine can do its job.