Can anyone identify the type of stain/stain causing agent?

Oct 29, 2013
6
The pool is 2 year old plaster pool. Only recently has this "staining" appeared. Brushing, even with a wire brush, does not help. The stain feels rough. Any thoughts?
 

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Re: Can anyone identify the type of stain/stain causing agen

:wave: Welcome to TFP!!!

Can you post a full set of test results? See HERE.

If it feels rough, I have a feeling it is likely calcium scaling ... test results may help confirm this.

How often do you test your water?
What do you use to chlorinate it?
 
Re: Can anyone identify the type of stain/stain causing agen

We just moved into the house a month ago. The problem appears to be getting worse every week. We are in Dallas, Texas. The weather as been in the 60-80s last couple of months. We have a new pool service that comes weekly to test and clean. They reported the following values:

10/21:
Chlorine: 3
pH: 7.6
TA: 90

10/29:
Chlorine: 3
pH: 7.6
TA: 90

They verbally told me the chlorine was at zero on 10/21 so they adjusted it. I am not sure what they use to chlorinate the water. They thought the chlorine could have exaggerated the existing stain. They also added shock on 10/21. They told me they thought the plaster was not cured properly. However, 6 weeks ago, the pool looked much better. Thoughts?

I thought it may be calcium scaling too. But doesn't it take a while to set in?
 

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Re: Can anyone identify the type of stain/stain causing agen

Well, it has had 2 years if the chemistry has not been maintained. You are missing some very important test results ... CH and CYA.

And not knowing what type of chlorine is being used could be making things worse. Read these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool

I would highly suggest you get one of the Recommended Test Kits and with some learning here, take control of your pool maintenance for yourself.

It could be a combination of calcium scaling (the roughness) and maybe some metals giving it the color???

You could try crushing up some vitamin C tablets in a sock of something and setting them on the stain and see if the color is faded/removed in a few minutes. That would confirm metals in addition to the roughness.
 
Re: Can anyone identify the type of stain/stain causing agen

Welcome to tfp, aghagar :wave:

As jbliz mentioned, make sure you purchase one of the appropriate test kits. Many of us have the tf-100 since it is the best value. A good test kit is imperative to maintaining your pool chemistry to avoid future problems.
 
Re: Can anyone identify the type of stain/stain causing agen

It will require a very close look and feel to determine whether the "roughness" is a deposit of calcium carbonate, or a loss of the surface material (plaster cream) resulting in an etched condition.
If the roughness is raised above the surface, then it could be a calcium deposit that is taking on iron for the yellow color.

Is the roughness more on the vertical walls, or on the horizontal flat surfaces?

It also could an iron staining issue which is adhering to the more porous areas of your plaster surface.
The porous areas are either due to aggressive water or from poor finishing practices, such as adding water while troweling. It becomes a long-term issue.
Not much can be done to rectify if due to a porous or etched surface.
 
Re: Can anyone identify the type of stain/stain causing agen

It appears pretty uniform across the pool. Perhaps more on the horizontal areas. If it's iron staining adhering to the more porous areas of the pool, can I draw the iron out and remove the stain?
 

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Re: Can anyone identify the type of stain/stain causing agen

It is generally very difficult to do so, but sometimes products like Jack's Magic or United Chemical work to remove that type of iron staining.
Potassium alum may also work.
When you determine whether the rough areas is a scale deposit or not, let us know.
 
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