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Thread: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

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    Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    For all you pool experts that like a challenging puzzle

    Last summer (2016) our pool was a little over a year old when the plaster quartz (QuartzScapes) started getting dark gray discoloration/staining/mottling. Our water was crystal clear and our chemicals were perfect (BBB & Taylor test kit) except the calcium kept rising which we assumed was from the new plaster.

    The pool was plastered spring 2015 and the temp was 105 degrees F. They did not tent the pool or run misters to cool down the plaster. I have read that plaster contractors sometimes add extra calcium to speed up the hardening but should only do it when it is cold out.

    Here's the real mystery:
    The gray mottling was everywhere except:
    - the Baja shelf was completely clear of any mottling and looked perfect.
    - And there was a path or strip about 18" wide down the middle of the pool from the shallow end to the deep end that was completely free of the staining/discoloration.
    Also, the mottling or staining was much worse in the spa than anywhere else in the pool.

    We tried every test we could find for staining:
    -Black algae or other organic cause, negative.
    -Metals, negative
    -Scale, negative
    -Marks from black pool vacuum wheels, negative

    We finally decided it was a bad case of plaster mottling and contacted the plaster contractor. I was ready for a big battle, but their customer service has been great. They agreed it was not our chemicals. They also did not know why the calcium levels kept going up. They couldn't figure out what was causing the mottling but agreed to drain the pool, and sand/polish the entire surface. We were happy they wanted to do that rather than an acid wash which I felt would make it worse. They did insist after sanding it to do a VERY light acid wash to rinse away the powder from sanding.

    After the sanding, the pool plaster looks great. We could still see the strip down the middle where had been clear of any mottling as it was now slightly bluer, like it had more blue quartz in it but it isn't too noticeable so we were okay with it.

    My concern with their approach is that they are not finding the root cause of the problem. Sanding only removes the discoloration, but without knowing what caused it in the first place, there's no way to know if it will happen again or how to prevent it.

    Then the HUGE AH Ha moment came. When they started refilling the pool, they put the hose over the side of the pool at the shallow end, and the water ran from the shallow end straight down the middle of the pool to the deep end in the EXACT same path or strip of pool floor where there had been NO mottling, and it was the exact same ~18" wide path. We moved the hose around a bit and no matter where the hose was, the water gravitated to that exact path so it is obviously slightly dipped down the center causing the water to follow that path every time. So that strip of plaster had much colder water running down it for hours when they first filled the pool after the original plaster job.

    Our second ah ha moment came when we remembered that when they originally filled the pool after plastering, they put one of the the hoses on the baja shelf, so the Baja shelf also had much colder water constantly running over it for many hours and the Baja shelf also had NO mottling/discoloring.

    Our third ah ha moment came when my spouse remembered that the spa was filled last so its plaster was in the hot blazing sun for the longest of anywhere in the pool, and the spa had the worse mottling of the whole pool.

    So we are surmising that the cold hose water (our tap water runs cold even in the summer unlike some other AZ areas) on the Baja shelf and the strip down the middle of the pool kept plaster cooler for several hours causing the plaster to cure a little slower in those areas than the rest of the pool plaster.

    So knowing what we know, what does it all mean for the future of our plaster? Does this mean the plaster was allowed to cure too fast in the heat and they should have tented/shaded the plaster and/or used misters to lower the temperatures? I know it got hot very fast that spring-- we had been having a cool spring, just 15 days earlier the high had been in the 70s. And what's causing the calcium to rise? Is it leaching out causing the mottling? After they filled the pool after sanding it, the calcium was 300 and now a week later it is up to 400.

    Please help me with this mystery.
    25'x37' L shaped: 4' play pool and 8.5' deep end, w/7x11 spa, 26k gallon, gunite w/plaster quartz, travertine coping, IntellifoVS x2, C&C Plus 520 cart filter, inline leaf trap, IC40 swcg, IntelliPH, IntelliTouch auto w/screen logic, MstrTmp 400k heat pump, 2 Intellibrite LEDs & 1 globrite, 3 sheers, 3 baja bubblers, 1 telescoping spa bubbler, 2 Venturi skimmers, TK-2600 kit. Built 2015.

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    Is this the right category to post this in?
    25'x37' L shaped: 4' play pool and 8.5' deep end, w/7x11 spa, 26k gallon, gunite w/plaster quartz, travertine coping, IntellifoVS x2, C&C Plus 520 cart filter, inline leaf trap, IC40 swcg, IntelliPH, IntelliTouch auto w/screen logic, MstrTmp 400k heat pump, 2 Intellibrite LEDs & 1 globrite, 3 sheers, 3 baja bubblers, 1 telescoping spa bubbler, 2 Venturi skimmers, TK-2600 kit. Built 2015.

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    Rokihunter's Avatar
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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    When filling a pool after plaster it is filled in the deep end first to prevent discoloration. If it was that hot out when you plastered I would probably have requested a fill by using trucked in water to shorten the fill time to reduce the time the plaster was exposed to the heat. Hopefully the polish evened out the color to a tolerable level for you. How many hoses did they use when filling?
    16x32 modified L, 512 sq ft, 15,000 gal gunite pool. 20ft 24" raised bond beam tiled with NPT lightwaves aquamarine. 3 color LED 24" Sheers by cmp called wonderfalls. 500 sq ft of Kool deck. Pentair equipment, Intelliflo VS 3HP, 420 CCP cartridge filter, Easy touch 4 w/IC40 SWG and wireless remote. 1 globrite and 1 intellibrite 5g pool light. Plaster will be Stonescapes mini pebble in aqua white. TF100 test kit and future dolphin robot.

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    Mod Squad pooldv's Avatar
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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

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    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    Thanks for the links, I've read all those posts as we have been trying to diagnose his issue since last summe and I've been scouring this site for help all this time, almost a year now, and those informative links are how I came to my conclusions but what none of those posts answer is my very unique sitiution so I was hoping someone could help me determine if the plaster needs to be chipped out and replastered or not based on my evidence. I was hoping someone like onBalance would chime in with their expertise.

    They used two hoses, one in the deep end and one in the shallow end.

    I'm running out of time for submitting a complaint via the AZ Registrar of Contractors if it comes to that, just a couple months left.

    I'll post some pics later but it was hard to get one of the strip down the middle.

    Thanks!
    25'x37' L shaped: 4' play pool and 8.5' deep end, w/7x11 spa, 26k gallon, gunite w/plaster quartz, travertine coping, IntellifoVS x2, C&C Plus 520 cart filter, inline leaf trap, IC40 swcg, IntelliPH, IntelliTouch auto w/screen logic, MstrTmp 400k heat pump, 2 Intellibrite LEDs & 1 globrite, 3 sheers, 3 baja bubblers, 1 telescoping spa bubbler, 2 Venturi skimmers, TK-2600 kit. Built 2015.

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    Mod Squad pooldv's Avatar
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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    Who is the manufacturer of the plaster? And have they been out to see it?
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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    What is the color of the quartz aggregate? Is the cement "white" or was there a color pigment added to change from white (normal cement color) to a particular color?
    It is unusual that "graying" didn't begin to show until a full year after the pool was finished. Therefore, there are other possibilities that could be the problem, such as calcium scaling.
    However, since the plastering contractor agreed to drain and polish the pool, perhaps it was a gray mottling problem.

    When did the draining and polishing take place? Last summer?
    Obviously, the water running down the middle of the pool floor had an effect on the color or shading of the plaster finish. But I would rule out the "cold water temperature" aspect as an issue or factor. Just a coincidence.

    Determining what happened would require a detailed analysis of the plaster finish, and inasmuch as you agreed to have the plaster contractor polish the pool and essentially are somewhat pleased with the results, it seems to me that waiting to see if the plaster turns gray again is what you may want to do. Before and after pictures would be helpful too.

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    They just polished/sanded it a couple weeks ago. We tested for scaling and it wasn't scaling and the contractor agreed. I thought the mottling would have happened sooner too. But the calcium keeps going up even though we add nothing but muriatic acid (by hand in winter and an injector in summer) and have a SWG (add bleach in winter) and CYA. I can't think what could be causing the calcium to continue rising and it seemed to escalate around the time the mottling started about a year ago, which was a year after the pool/plaster was finished. So the only thing I can think is they used too much calcium and it started leaching out of the plaster causing the mottling.

    The quartz aggregate is called QuartzScape by National Pool Tile and the color is called Super Blue, it is one of their lighter colors. It has a lot of aggregate in it and I would assume the plaster is slightly colored. I'll try to find a sample picture of the QuartzScape to post. I can't find any contact information to have the manufacturer come look at it.

    I posted about this a year ago when it started with pictures but I am having trouble posting new pictures for some reason but I'll try to find the link the thread with the pictures.

    Thanks!
    25'x37' L shaped: 4' play pool and 8.5' deep end, w/7x11 spa, 26k gallon, gunite w/plaster quartz, travertine coping, IntellifoVS x2, C&C Plus 520 cart filter, inline leaf trap, IC40 swcg, IntelliPH, IntelliTouch auto w/screen logic, MstrTmp 400k heat pump, 2 Intellibrite LEDs & 1 globrite, 3 sheers, 3 baja bubblers, 1 telescoping spa bubbler, 2 Venturi skimmers, TK-2600 kit. Built 2015.

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    IMG_4074.jpgIMG_5584.jpgIMG_9207-2.jpg

    This is when it first started, it continued to get worse.
    25'x37' L shaped: 4' play pool and 8.5' deep end, w/7x11 spa, 26k gallon, gunite w/plaster quartz, travertine coping, IntellifoVS x2, C&C Plus 520 cart filter, inline leaf trap, IC40 swcg, IntelliPH, IntelliTouch auto w/screen logic, MstrTmp 400k heat pump, 2 Intellibrite LEDs & 1 globrite, 3 sheers, 3 baja bubblers, 1 telescoping spa bubbler, 2 Venturi skimmers, TK-2600 kit. Built 2015.

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    Here's the color samples, our quartz plaster color is the Super Blue. It's called QuartzScapes by NPT. I included the other colors so you could see it is quite a bit lighter than most of their color selections. I was told lighter was less likely to mottle.

    25'x37' L shaped: 4' play pool and 8.5' deep end, w/7x11 spa, 26k gallon, gunite w/plaster quartz, travertine coping, IntellifoVS x2, C&C Plus 520 cart filter, inline leaf trap, IC40 swcg, IntelliPH, IntelliTouch auto w/screen logic, MstrTmp 400k heat pump, 2 Intellibrite LEDs & 1 globrite, 3 sheers, 3 baja bubblers, 1 telescoping spa bubbler, 2 Venturi skimmers, TK-2600 kit. Built 2015.

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    Picture of pool plaster as it should look, it's a couple of months old and before mottling started, sorry for the weird angle.



    After Mottling started, can see baja shelf is clear of mottling.




    Couple weeks ago:
    Starting drain for sanding pool plaster, can see baja shelf has no mottling:




    Pictures as pool being drained for sanding, look darker because the pool was empty and shaded:












    A couple pictures when mottling started last summer that you can sort of see the clear strip down the middle where there is no mottling, second picture is same with arrows pointing to strip of clear of mottling, a little hard to see due to tree & cloud shadows on water. This strip of clear plaster is where the hose water ran when pool was being filled, and also on the baja shelf.






    Let me know if any of the links don't work.

    Thanks!
    Last edited by Millty; 03-30-2017 at 04:33 AM. Reason: fixed urls
    25'x37' L shaped: 4' play pool and 8.5' deep end, w/7x11 spa, 26k gallon, gunite w/plaster quartz, travertine coping, IntellifoVS x2, C&C Plus 520 cart filter, inline leaf trap, IC40 swcg, IntelliPH, IntelliTouch auto w/screen logic, MstrTmp 400k heat pump, 2 Intellibrite LEDs & 1 globrite, 3 sheers, 3 baja bubblers, 1 telescoping spa bubbler, 2 Venturi skimmers, TK-2600 kit. Built 2015.

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    Mod Squad pooldv's Avatar
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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    You can copy the IMG code to the right of the pic in Photobucket and paste it in your post so that the pics will show up in your post. That way people don't have to click out of the forum.
    TFP Moderator
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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    It does not appear that your Super Blue Quartzscapes product contains a "color pigment" but you should confirm that with the plaster contractor. Therefore, the discoloration problem is not likely to be a color pigment "issue" or problem.
    Another reason for graying of white cement (in addition to adding too much calcium chloride) can be due to simply over-troweling when the new and fresh plaster has become too stiff or hard to trowel properly. But it shouldn't have taken a year to become visible. That is a question with your pool.

    At this point, it is up to you to decide whether to pursue this with the plaster contractor or the ROC.

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    Thanks @ Pooldv for letting me know how to post the pictures, I knew there must be an easier way, doh!

    Thanks @onBalance! Wouldn't you know that I have the weird situation that is hard to determine the exact cause-my personal gray cloud follows me everywhere.

    So it looks like it is either:
    1. Too much calcium
    and/or
    2. Over troweling

    Could it be also be caused or escalated by the heat on the day it was plastered? It was 105 and the heat had come on suddenly that year. I've read they should tent/shade and add misters to slow down the curing process, but they didn't.

    I told the contractor that I thought they could have over/hard troweled, and he said no way, but of course he would say that. Would over troweling cause the calcium to rise like it is? I don't think they were used to doing pools as large as mine (on the largish size for AZ) and deep pools aren't as common in AZ anymore either plus it had a spa and lots of details like 2 benches and a love-seat. They used two crews and you could tell they were not used to working together, some guys standing around doing nothing, others working like mad.

    I remember the foreman was almost two hours late and the guys all showed up but weren't allowed (per their rules) to come on our property until the foreman showed up. They lost a bunch of setup time that they needed before the plaster showed up because the plaster schedule is set the night before and can't be changed--it is set in stone, ha ha. So the hot load may have been sitting out there longer than it should have especially in the heat we had. They also lost a couple hours of the cooler morning temps.

    The contractor has been pretty good in that they decided to sand/polish the pool instead of blaming us as I've heard some do, but I don't know what that does to the longevity of the plaster taking off a layer like that. And they also sanded right over our glass tile inlays even though I made sure they knew not to do that. Totally ruined all the tile inlays. They had to keep the pool empty an extra day and come out the next day and chip out all the tile and replace it.

    Argh, wish I could figure out what to do and had more time to decide but I have until the end of May to file with the ROC. I hate to go through the ugly process of filing a complaint through the ROC but I don't want a gray stained pool again a year from now or deteriorating plaster and then have to hire a lawyer to get it rectified.

    Sorry to pull my pity card, but I have cancer and just don't need this on top of everything else. We spent a lot of money on our pool and I want my kids to have a nice pool. I spent nearly a year planning and contracting our pool (I designed and contracted it myself) and then spent this year battling cancer, I just don't need any more battles. OK, pity party over.

    Thanks everyone!
    25'x37' L shaped: 4' play pool and 8.5' deep end, w/7x11 spa, 26k gallon, gunite w/plaster quartz, travertine coping, IntellifoVS x2, C&C Plus 520 cart filter, inline leaf trap, IC40 swcg, IntelliPH, IntelliTouch auto w/screen logic, MstrTmp 400k heat pump, 2 Intellibrite LEDs & 1 globrite, 3 sheers, 3 baja bubblers, 1 telescoping spa bubbler, 2 Venturi skimmers, TK-2600 kit. Built 2015.

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    Hot temperatures can play a role, but a lot of pools are plastered in those conditions. The fact is that hot and dry conditions do not speed up the curing (hydration) process, and when the plaster dries out, it actually stops the hydrating (hardening) process. Moisture is needed for continued hardening. That is why tenting should be and is needed on hot days. If the discoloration is internal to the plaster, then there is a good chance that discoloration will begin to appear again in about a month. The discoloration issue may not be necessarily a durability issue that would shorten the life-span of pool plaster. That is the best I can suggest.

    However, I would be interested in knowing more precisely how much and how soon the calcium level is rising with the pool water. How accurate are the calcium tests, how much is the increase, and over what period of time have you documented the calcium rise? I assume you understand the water evaporation issues and refilling with water for swimming pools in Arizona which would also cause the calcium level to increase regularly.

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    First time to post to a forum but I'm desperate...
    Our pool was finished about 5 weeks ago...from the first week after the finish, we noticed a large discolored area in the deep end of the pool. After researching online, we found that this is called gray mottling or discoloration. Our builder claimed it was normal and this is how all pools look and that we needed to continue brushing.....BTW, our plaster is Quartz Scapes, Quartz Brite. We ended up hiring someone to help with the brushing so that the pool was brushed several times a day. After 2 weeks of this, the pool was still collecting a massive amount of "plaster dust" and the discoloration was not going away.
    Our pool builder finally agreed to take another look and settled on a fix....drain the pool and acid wash the whole thing.
    We thought this fixed it...but the day the pool was filled up again, we noticed another problem...a white film was attaching itself to the entire pool..not only had the discoloration in the deep end come back, but now a sandy white substance had started to form..it has continued to spread and cover everything. We have brushed, scrubbed...it's not coming up.
    We are taking our water in twice a week to Leslie's where they test the water for balance. We started this the day after the acid wash. Our calcium levels are holding at 220 - 230. PH is low...
    I have been talking with the NPT rep in hopes that they can give sound advice on how to move forward. I am terrified that once we bring our builder back into this, the blame for this mess is going to be placed on us, the owners. After researching online, it sounds like the symptoms we are experiencing can be caused by in-proper application of the plaster to begin with. Any advice from pool builders or restoration companies would be greatly appreciated...

    I have posted this message on a few different threads...

    photos attached
    Pool pic 1.jpgpool pic 4.jpgPool pic 2.jpg

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    Re: Help! with pool plaster quartz discoloration mystery, it's so weird! Please help!

    @onBalance, thanks for the information. I am going to test the calcium again tomorrow and continue to test at least weekly. I'll update on this post what happens with our calcium levels.
    25'x37' L shaped: 4' play pool and 8.5' deep end, w/7x11 spa, 26k gallon, gunite w/plaster quartz, travertine coping, IntellifoVS x2, C&C Plus 520 cart filter, inline leaf trap, IC40 swcg, IntelliPH, IntelliTouch auto w/screen logic, MstrTmp 400k heat pump, 2 Intellibrite LEDs & 1 globrite, 3 sheers, 3 baja bubblers, 1 telescoping spa bubbler, 2 Venturi skimmers, TK-2600 kit. Built 2015.

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