Spots on plaster... Help been through 2 pool guys no help

[Lwool2]

Hi, our pool is just hitting the 1 yr. mark. All was fine and then we decided to hire a pool guy. The first one was late, spent all of 5 min here then left, etc. so we nixed him pretty quick.

The 2nd one we kept for 3 months. At the beginning I told him about the light stains on the plaster and showed him. He said getting the chemicals right would fix it. He seemed to know what he was talking about so we hired him. At the end of the quarter he wanted to renew so I went to look at the pool and it was worse!

I let him go but now I am trying to fix on my own. I have gotten the water tested and all things are in the good range. I put some phos free in because that's all it needed according to WPS testing. But stains are still coming. I tried putting lemon and scrubbing to no avail. Now I have a chlorine tab to see if that does anything (the pool guy told me to do this). So far the only thing happening w the tab is it is turning purple on the bottom of the tab itself. Nothing to the plaster.

I am exhausted with trying to figure this out... Please HELP my plaster is staining and I see no way out.

Thanks for any help at all.

1yr old newbie on her own

 

[JasonLion]

Re: Spots on plaster... Help been through 2 pool guys no hel

Could you post a full set of water test results? Also, what color are the spots? And are they rougher, the same, or smoother than the surrounding plaster?

 

[Butterfly]

Re: Spots on plaster... Help been through 2 pool guys no hel

Some pics of the spots would also be helpful.

Welcome to the forum

 

[Lwool2]

Re: Spots on plaster... Help been through 2 pool guys no hel

Ok they are brownish, rough and I will upload pic once I figure out how.

Water results

Free Chlorine 5.0
Total Chlorine 5.0
Combined Chlorine 0.0
Ph 8.2
Hardness 425
Alkalinity 115
Cyanuric Acid 100
Copper not run
Iron not run

The guy told me to add 2 pt Muriatic Acid so I did.

 

[Lwool2]

Re: Spots on plaster... Help been through 2 pool guys no hel

Sorry just read ur what to post. The water is clear. The spots have progressively gotten worse over the last 5 months. Which is when the pool began having very small spots and the plaster looks kind of marbled very light greyish color.

 

[JasonLion]

Re: Spots on plaster... Help been through 2 pool guys no hel

Your description and your water test results both point towards calcium scaling. Calcium scaling occurs when some combination of PH, TA, and CH are too high. Your PH is way too high, while your TA and CH levels are both a little to high, and that combination is enough to push you into calcium scaling.

I suggest that you start working on lowering TA, which will also bring the PH down. There are instructions on how to do this in Pool School.

Removing calcium scale is work. The traditional approach is to drain the pool and do a manual acid wash. If there isn't to much you can also remove it by essentially grinding it off with a pumice stone.

By the by, your CYA level is way too high. That wouldn't affect the staining one way or another, but it does tend to make it pool difficult to manage.

 

[Lwool2]

Re: Spots on plaster... Help been through 2 pool guys no hel

WOW. Thank you so much. Hmmm.... I will read on how to lower the TA. I think we are going to drain the pool try the pumice stone if that does not work then I will do an acid wash while the water is out. It is so frustrating because one person says one thing and another a differing thing. I was told it is good to have the CYA high because this will keep the equipment running better (not as hard) and therefore last longer.

One more question, what concentration of MA do I use, if the pumice stone does not work? Now to read on lowering TA

Thank you again,
Lisa

 

[JasonLion]

Re: Spots on plaster... Help been through 2 pool guys no hel

When doing an acid wash there is a balance between speed and complexity/skill required. Higher concentrations of muriatic acid go more quickly, but require more skill to keep under control. I suggest you start with one part acid to five parts of water. If that seems easy to hand try 1 to 4, and so on.