Stubborn Dirt Stains

[dmtranman]

I moved into my house 2 years ago and over the last two years I've noticed my pool plaster now has more and more dirt stains. The stains are on the bottom of pool, steps, and spa seats. There doesn't seem to be dirt stains on the walls.

I brush once a week but for some reason there seems to be more and more dirt stains. The stains don't seem to brush off either so it's slowly gotten worse over the last 2 years.

The pool is about 10 years old and I have noticed that the plaster is some what rough but not extremely rough. Not sure if this is why the dirt stains won't brush off.

Any suggestions would be really helpful. Thanks!

 

[duraleigh]

Welcome to the forum :lol: Rather than dirt, (dirt would brush off) think of them as either organic stains or mineral deposits. Chlorine will usually cure the organic stains, the other is tougher.

Pics will help but a full set of test results is the only way to begin identifying the stains.

 

[dmtranman]

Thanks for the reply! I've posted some pics. If it is an organic stain how do I use chlorine to remove it. Are you suggesting some how spot treating it with chlorine?

 

[duraleigh]

Are you suggesting some how spot treating it with chlorine?

No. Elevating the FC levels above normal until the stains disappear.

Still just guesses, tho, until you can get some test results.

 

[dmtranman]

How do I test stains?

 

[duraleigh]

You don't. You test the pool water for....

FC
CC
pH
TA
CH
CYA

If you are not familiar, those abbreviations can be found in Pool School. Your own testing is by far the best but it sounds like you do not test so getting a Pool Store to do it for you is a start. Don't buy anything from them but get those test results and post them back up here.

 

[dmtranman]

Got it, my problem is all my tests are ok done by me and pool store and I still have the dirt staining.

 

[Richard320]

Looks like Calcium scale to me. It's not gleaming white like a movie star's smile, it tends to be greyish or tannish in my experience.

"ok" isn't really the test results we were looking for. With some actual (and accurate) numbers, it's no problem to get the Calcium Saturation Index, which would end a lot of the speculation.

My suggestion: get Pool Schooled.

 

[zea3]

Got it, my problem is all my tests are ok done by me and pool store and I still have the dirt staining.

Please post the results for your most current tests. Certain problems are associated with specific water parameters. Without those test results we can't begin to troubleshoot your problem. Just saying the results are o.k. does not give us enough information to work with.

 

[duraleigh]

dmtranman,

At the risk of sounding rude (and I don't mean to), your water is not "ok". If it was, the staining wouldn't be there.

 

[dmtranman]

Thanks for all the responses. I just went to have my water tested at the pool store again today. Here are the results:

FAC - 3.0
pH - 7.6
TA - 90
CYA - 38
Calcium Hardness - 450
TDS - 1200
Copper/Iron - .3
Phosphates - 200

Could the stains be due to calcium buildup? The plaster is a bit rough and we do have hard water at our house.

 

[duraleigh]

Probably. That CH is a little higher than ideal and, if you have coupled it with high pH from time to time, that's enough to cause scaling (calcium buildup)

The iron test is not very good news, either. As a rule .3ppm or above can lead to iron precipitation. I would rule that out first. Take some cheap Vitamin C tablets and crush them in a sock and then hold them on the stained area for a couple of minutes. If the Vitamin C does not noticeably lighten the stain, then it is not iron Why not try that first?

Do you have reason to believe your pH gets to 8.0 or higher from time to time?

 

[dmtranman]

Yes, I'm guilty of letting my pH get as high is 8.0 from time to time. I usually hovers around 7.6-7.8 but some times I'll skip adding acid one week and next week I'll check and it's at 8.0.

I tried the vitamin c test and it looks like it lightened the stain.

Looks like I have an issue with calcium scaling and metals staining. Should I do the ascorbic treatment for the metal staining? Any other options? Leslie's pool store told me to try a product called Metal Free.

I guess for the calcium staining I need to do a drain and acid wash?

Any other suggestions would be great. Thanks for all your help!

 

[duraleigh]

If it was my pool, I think I would try to lower the pH a BUNCH to see if you can dissolve the calcium. Read this thread....

2nd-times-a-charm-no-drain-acid-wash-t39173.html?hilit=no%20drain%20acid%20wash

It's the cheapest and easiest solution and , in your case, I think it might work. Make VERY sure you understand it before you do it and ask lot's of questions. Everyone here will help.