Need help removing staining from new fiberglass pool

[rmb212]

I am in need of some advice and direction on this and any help is much appreciated.

The paver crew I hired to do travertine pavers and coping had poured the coping bed/ beam too high and I caught it prior to them laying the coping and made them correct it so the coping would either be flat or slightly pitched away from the pool. So, they grinded down the concrete to the right height which put a tremendous amount of concrete dust in the pool. I cleaned all the dust thoroughly out of the pool, filter and equipment. However, when I went to scrub the walls which I though was just dust settled on the walls, It would not come off and they are in fact stained. Most people don't notice and it can only be seen really at dusk but is undoubtfully there and it drives me nuts.

The staining is greyish and I suspect it may be metal staining but am not 100 percent sure. I am very able person but am not real experienced with water chemistry, just know enough to take the test and balance it. I have tried to contact several pool service companies but haven't had any luck even getting someone out to even take a look at it. It may be hard to see in the pictures but its there.

 

[Texas Splash]

Photos don't seem to do us justice, or maybe it's just me and my eyes. I doubt it's metals (iron), but you can try to rub a vitamin C tablet on a stained area to confirm. If it's iron, the vitamin C tablet should have an immediate effect. If that doesn't work, it may be something residual from the plaster products. You can try lightly sanding with a 1,000 wet/dry sandpaper. You could even go a bit more aggressive (600-800) if needed, but always start gently in a small test area to ensure you are happy with the results.

 

[rmb212]

I know the photos don't do it justice, I tried to mark it where the stains are. The areas that are marked are stains not water or camera fluctuations and its like this throughout the whole pool. I did try lemon had verry little effect. Also tried wet sanding, had some paper left over from boat gel coat project, did help but not enough to consider doing the whole pool with a snorkel underwater id be there for a month and had to get aggressive with it to make a difference, dont want to risk going through the gelcoat. I will try to get some vitamin c tablets.

 

[rmb212]

Also pool was bright white prior to the concrete dust getting in. Thought it may be metal from compounds used in concrete. It really just looks like the dust is still on the walls and could be scrubbed right off but nothing removes it. I wouldn't mind paying a professional to diagnose and fix if I could find one

 

[duraleigh]

If that's concrete dust on the walls it's mostly calcium. Probably the best way to approach that is to keep your pH abnormally low to see if that will turn the dust into solution. I don't know that it will but it's an easy, inexpensive attempt.

Can you post a current and complete set of test results?

 

[rmb212]

Thanks for the input. I will test and repost. Last test at Leslie's showed the alkalinity slightly high and I used the recommended amount of dry acid to lower. I may invest in a more accurate home test kit.

 

[duraleigh]

Thanks for the input. I will test and repost. Last test at Leslie's showed the alkalinity slightly high and I used the recommended amount of dry acid to lower. I may invest in a more accurate home test kit.

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[rmb212]

Thank you for the welcome duraleigh.

I have since ordered the tft-100 salt test kit and will update results once received.

 

[rmb212]

So I received the test kit and here are the results.
PH: 8.2 possibly higher
FC: 6.0 ppm no combined chloramines, so TC is 6.0
TA: 100
CYA: 20 ppm
CH: 325 ppm
Salt: 4800 ppm

I have since lowered the salt cell to the lowest setting. I know I need to lower PH and chlorine and balance everything, but what would be the next steps to identify the grayish staining throughout all the pool walls? I was thinking about trying jacks magic process ,maybe someone has experience with this product.

 

[duraleigh]

Lower your pH. Get it down to around 6.8 - 7.0 and keep it there. Brush the pool twice daily if you can and run the pump 24/7. That should dissolve the concrete dust and/or filter it out. See if you notice a difference after 48 hours. Please don't try a bunch of magic potions. Let us know your progress

 

[rmb212]

Thank you. I did lower the ph to about 7.4 after testing, but I will try your advice this weekend. If it works or doesn't work I'm assuming I should bring the ph back up right after correct?

 

[duraleigh]

I'm assuming I should bring the ph back up right after correct?

Essentially correct. Having the pool at 6.8 pH for a couple of days will do no harm. I am hoping you will see the concrete dust start to disapate during this process so give it plenty of time to do it's job. If you can tell it is working, I would leave pH at 6.8 until the ce3ment was gone and then bring it up to around 7.4 or so.

You are NOT in dangerous territory at 6.8. Let us know how it goes.

 

[ferretbone]

duraleigh has the best first advise. Lower the Ph and that dust will loosen up. Happens all the time with fine sands and dust, and I lower the ph and keep brushing it until it's all broken loose.

 

[rmb212]

So I lowered the PH to around 6.8 and scrubbed several times and ran pump continuously for 48 hours had no effect, not even a little bit. Had to add what seemed to be a lot more dry acid than what was recommended per gallon, over several days of course, to get it that low. About 4 pounds

I did get a stain ID kit from Jacks Magic prior to posting and it came in so I used it just to see if anything would take it off, don't worry didn't do any magic potions or treatments, just a test spot. To my surprise, their stain solution #1 and #2 combined ( iron scale treatment) immediately cleared it, which were done according to the instructions on a small test area. Just a couple teaspoons of it cleared a pretty large area . I attached some more pics bc now its much easier to see the staining. Just to the side of the step is the test area that turned the pool back bright white.

Keeping in mind that the "jacks Magic" is really vague on specific kind of stain it is, but now that I know it can be removed and that its likely metal. Do you have any further recommendations?

 

[Bperry]

So I lowered the PH to around 6.8 and scrubbed several times and ran pump continuously for 48 hours had no effect, not even a little bit. Had to add what seemed to be a lot more dry acid than what was recommended per gallon, over several days of course, to get it that low. About 4 pounds

I did get a stain ID kit from Jacks Magic prior to posting and it came in so I used it just to see if anything would take it off, don't worry didn't do any magic potions or treatments, just a test spot. To my surprise, their stain solution #1 and #2 combined ( iron scale treatment) immediately cleared it, which were done according to the instructions on a small test area. Just a couple teaspoons of it cleared a pretty large area . I attached some more pics bc now its much easier to see the staining. Just to the side of the step is the test area that turned the pool back bright white.

Keeping in mind that the "jacks Magic" is really vague on specific kind of stain it is, but now that I know it can be removed and that its likely metal. Do you have any further recommendations?

View attachment 461537View attachment 461538

Any idea where the metal came from if it is metal? There’s no metal in concrete. How long have you been using Leslie’s for testing and have you ever added any of their products?

Side note, stay away from the dry acid if you have a SWCG. That adds sulphates which can damage it.

 

[rmb212]

I was not aware that the dry acid would hurt that, so thanks, would muriatic be batter for lowering PH? . It is a new pool installed around May of this year and I did use their products to initially balance the water however the water, according to their test, only needed salt, a little hardness and alkalinity, I guess it got me close. By Duraleigh's advice, I ordered a tf-100 and have been doing my own testing and as he stated the pool store was way off. The water is fairly well balanced now and has always been clear.

Concrete, however does have some metals in the aggregate and some trace heavy metals in the mix for reinforcement. Not sure if there is enough to cause "metal staining" but it was for sure from the dust. pool was bright white, and after introducing the dust from the grinding, which was a lot, the entire pool was stained there after. Should of done the pavers myself but ran out of time and am paying for it in the long run. The whole Install side I'm very familiar with as I did the development where I'm at but never really had any knowledge of water chemistry, you just don't know what you don't know yet. I am learning and know enough not to just throw a bunch of chemicals at it.