Dirt Looking Stain

[tppflorida]

Hello,

I have a pool that I just took over that has what appears to look like dirt on the pool walls and floor. After brushing and vacuuming, it became evident very quickly that it wasn't dirt. The pool has had metal control added from day 1 and the pool is only about six months old.

In addition, the stain is nearly invisible in the sunlight, but clear as can be when it's cloudy out. Unfortunately, the stain was not noticed by the home owner until just recently. The stains have incredibly smooth outer edges in appearance. If I didn't know better, I would say somebody vacuumed the pool and completely missed an entire section... that's how smooth the edges of the stain look.

Having said that, my best guess given the circumstances, is that the pool was not properly cured. I don't know that for sure though, so I'm asking for anybody's help that may have experienced this themselves.

My questions are:

1) what causes this stain
2) how to get rid of the stain
3) how to prevent future, similar stains

Thanks in advance for your help... I found this site from the old poolforum.com site and couldn't be happier to have located it.

Michael

 

[JasonLion]

Do you have water test numbers?

 

[tppflorida]

I'll have those Thursday for you... I'll post then.

Michael

 

[mbar]

You can try crushing up some vitamin C tablets putting them in a sock and rubbing on the stain. If this lightens the stain, then it is a mineral stain (metals). These stains can be removed with ascorbic acid along with a sequestering agent. When you post your numbers, we will be able to help you more

 

[tppflorida]

I forgot to ask... do you need numbers other than chlorine, ph, and alkalinity?

Michael

 

[JasonLion]

It would also be good to also get a calcium hardness level if you possibly can.