No. See my post #6. My plaster looks very much like yours.
Yes, your PB, like mine, probably will blame the water chemistry. This may come down to how far you want to go with this.
Gray mottling problem
- Thread starter yardoasis
- Start date
No. See my post #6. My plaster looks very much like yours.
Yes, your PB, like mine, probably will blame the water chemistry. This may come down to how far you want to go with this.
Ask them how many pounds of calcium chloride they added to each 100 pounds of cement in the plaster mix.
Then tell them that you can have the plaster analyzed by a cement lab to verify their figure.
Then tell them that you can have the plaster analyzed by a cement lab to verify their figure.
Gray mottling problem: PB Visit
Ok, the PB came to take a look... and oh, where do I begin. Nice fellow, and he said it could be 1) bad water chemistry, 2) hardness of the water, 3) workmanship. This is gonna be long, and if you don't feel like reading, just skip to the summary at the end.
I told him about how I've been doing my water chemistry, keeping CH between 200-400, mostly at 300 or below... and most importantly CSI as close to 0 as possible. He said I've been doing a very good job with the water chemistry, but still maintained that the water is VERY hard in the greater Houston area. He named some towns and neighborhoods that have the same problems, and it all depends on the city water, the source, and how hard they allow it to be. He said that one town could have very hard water with plaster problems, and the next town 5 miles away would have no problems. Since he kept saying the water here is "really really bad", I checked a water hardness map:
http://www.h2odistributors.com/water-hardness.asp
Turns out our water here is "moderately hard", or maybe I'm on the line between "moderately hard" and "hard", at least according to this map. Can water really vary that much from town to town, like the PB was saying? Btw, I tested my fill water a month ago and CH was 200. I'll retest that today just to be sure. I know that places like Arizona and Utah have water that is even harder, and surely they don't have plaster problems in every pool there??
They offered to acid wash the bottom half of the spa as a test. So they drained the spa, and acid washed it. Only the organic spotty stains came right off (dissolved would be the better word), but the gray mottling remained. It looks EXACTLY the same before and after the acid. The subs still said that they could acid wash the entire pool and there would be less stains. I was totally unconvinced, and peppered the PB with more questions about acid washing, life of the plaster, etc. He said even if they did an acid wash, the stains could come back later because the water is so hard. So I asked, "if the stains are going to come back, then what's the point in doing an acid wash?" He agreed, and said if it were him, he'd save his money and in 5 years, upgrade the plaster to something that would not allow the mottling to appear.
Then I asked them how much calcium chloride they put in the plaster, and they said they did NOT put any. They were adamant about it, and said it should be 0%. Then he asked me when the plaster was installed (March), and he said it could be 1% because they put a little in when the weather is a little cold. I told him that I'll get a plaster sample tested at a lab to verify his claim. I thought that would make him nervous, but on the contrary, he happily encouraged me to do so, and ordered one of his guys to get a sample off the drain area. They did, and I bagged the sample. PB told me to let him know once I got the results.
SUMMARY:
1. As a test, PB drained spa and acid washed bottom half. Organic spots came off, gray mottling looks exactly the same.
2. PB went on and on about how hard the water is in Texas, and lots of pools have the same problem.
3. PB and I agreed there's no point in an acid wash, told his subs to get me a plaster sample, and I'll send it to a lab to verify their claim of no calcium chloride in plaster.
4. PB said there's nothing more I can do, except upgrade to a "better" plaster.
All in all, it was a civil conversation and he was a very nice guy, but it feels like there's nothing I can do, except hope the test comes out more than 1%... if it did, then the PB would "take care of it".
Ok, the PB came to take a look... and oh, where do I begin. Nice fellow, and he said it could be 1) bad water chemistry, 2) hardness of the water, 3) workmanship. This is gonna be long, and if you don't feel like reading, just skip to the summary at the end.
I told him about how I've been doing my water chemistry, keeping CH between 200-400, mostly at 300 or below... and most importantly CSI as close to 0 as possible. He said I've been doing a very good job with the water chemistry, but still maintained that the water is VERY hard in the greater Houston area. He named some towns and neighborhoods that have the same problems, and it all depends on the city water, the source, and how hard they allow it to be. He said that one town could have very hard water with plaster problems, and the next town 5 miles away would have no problems. Since he kept saying the water here is "really really bad", I checked a water hardness map:
http://www.h2odistributors.com/water-hardness.asp
Turns out our water here is "moderately hard", or maybe I'm on the line between "moderately hard" and "hard", at least according to this map. Can water really vary that much from town to town, like the PB was saying? Btw, I tested my fill water a month ago and CH was 200. I'll retest that today just to be sure. I know that places like Arizona and Utah have water that is even harder, and surely they don't have plaster problems in every pool there??
They offered to acid wash the bottom half of the spa as a test. So they drained the spa, and acid washed it. Only the organic spotty stains came right off (dissolved would be the better word), but the gray mottling remained. It looks EXACTLY the same before and after the acid. The subs still said that they could acid wash the entire pool and there would be less stains. I was totally unconvinced, and peppered the PB with more questions about acid washing, life of the plaster, etc. He said even if they did an acid wash, the stains could come back later because the water is so hard. So I asked, "if the stains are going to come back, then what's the point in doing an acid wash?" He agreed, and said if it were him, he'd save his money and in 5 years, upgrade the plaster to something that would not allow the mottling to appear.
Then I asked them how much calcium chloride they put in the plaster, and they said they did NOT put any. They were adamant about it, and said it should be 0%. Then he asked me when the plaster was installed (March), and he said it could be 1% because they put a little in when the weather is a little cold. I told him that I'll get a plaster sample tested at a lab to verify his claim. I thought that would make him nervous, but on the contrary, he happily encouraged me to do so, and ordered one of his guys to get a sample off the drain area. They did, and I bagged the sample. PB told me to let him know once I got the results.
SUMMARY:
1. As a test, PB drained spa and acid washed bottom half. Organic spots came off, gray mottling looks exactly the same.
2. PB went on and on about how hard the water is in Texas, and lots of pools have the same problem.
3. PB and I agreed there's no point in an acid wash, told his subs to get me a plaster sample, and I'll send it to a lab to verify their claim of no calcium chloride in plaster.
4. PB said there's nothing more I can do, except upgrade to a "better" plaster.
All in all, it was a civil conversation and he was a very nice guy, but it feels like there's nothing I can do, except hope the test comes out more than 1%... if it did, then the PB would "take care of it".
The PB is misleading you about the "water hardness" issue. For home use, water that has 200 ppm of hardness is considered "hard." But for plaster pools, it requires a minimum of 200 ppm of hardness for proper water balance. In fact, pool water can have as much as 500 ppm without being considered overly hard. So that means your pool water (between 200 and 400 ppm) is not considered to be overly hard or out of balance.
Also, high water hardness can cause calcium scaling, and calcium scaling can be easily removed by an acid wash. So the PB should explain why the discoloration did not disappear with his acid wash. He should also explain why the gray discoloration is smooth and is not rough like sandpaper which is what calcium scale feels like.
And you are right, there are many pools in Arizona that have very high hardness (over 500 ppm), and most do not have calcium scaling or don't have the gray discoloration that your pool is experiencing.
In regards to an upgrade pool plaster such as quartz finishes; they can also turn gray from improper plastering practices. So there is no guarantee that it won't happen again. Also excessively hard pool water could also "scale" any other kind of pool plaster, be it quartz or pebble finishes. And acid washes fixes that problem also. So the PB is wrong - it is not a water hardness problem.
Also, high water hardness can cause calcium scaling, and calcium scaling can be easily removed by an acid wash. So the PB should explain why the discoloration did not disappear with his acid wash. He should also explain why the gray discoloration is smooth and is not rough like sandpaper which is what calcium scale feels like.
And you are right, there are many pools in Arizona that have very high hardness (over 500 ppm), and most do not have calcium scaling or don't have the gray discoloration that your pool is experiencing.
In regards to an upgrade pool plaster such as quartz finishes; they can also turn gray from improper plastering practices. So there is no guarantee that it won't happen again. Also excessively hard pool water could also "scale" any other kind of pool plaster, be it quartz or pebble finishes. And acid washes fixes that problem also. So the PB is wrong - it is not a water hardness problem.
Re: the upgraded quartz finish, my quartz finish also has the mottling problem. I just live with it.
I emailed the PB again, pushing for another explanation for the gray mottling and I gave them a link to the water hardness map saying that our water isn't that hard.
Well, I just got home and I looked at the spa, it seems to have cleared up quite a bit. This is weird, immediately after the acid wash, it looked the same, but apparently after several hours, it whitens noticeably. 
EDIT: Here's a pic. If you look closely, you can see the line (couple inches below the tile) between untreated plaster and below that has been treated with acid. This is the spa part only. It's NOT perfect by any means, but it looks considerably better.
PB said if I acid washed the pool, he said the stains might come back in a few months. His reasoning was hard water, but if I maintained proper chemistry, the stains won't come back?
EDIT: Here's a pic. If you look closely, you can see the line (couple inches below the tile) between untreated plaster and below that has been treated with acid. This is the spa part only. It's NOT perfect by any means, but it looks considerably better.
PB said if I acid washed the pool, he said the stains might come back in a few months. His reasoning was hard water, but if I maintained proper chemistry, the stains won't come back?
I requested a full water quality report from my municipal water entity, and they quickly got back to me.
Looks like the hardness of my city water is 151 mg/L. Is that the same as 151 ppm? They also have grains to measure hardness, and I'm at 8.8. Compared with other water districts, I admittedly have harder water than most others, but not the hardest. I'd say I'm in the top 30% hardest of my county.
Good thing I have little or no iron at 0.01 mg/L while a few others have more than 0.20 or 0.30, so that definitely rules out iron for sure.
Looks like the hardness of my city water is 151 mg/L. Is that the same as 151 ppm? They also have grains to measure hardness, and I'm at 8.8. Compared with other water districts, I admittedly have harder water than most others, but not the hardest. I'd say I'm in the top 30% hardest of my county.
Good thing I have little or no iron at 0.01 mg/L while a few others have more than 0.20 or 0.30, so that definitely rules out iron for sure.
If an acid wash removes some of the gray mottling discoloration, it often returns a few weeks after the acid wash, so it is too early to judge the results, as the PB told you.
But the PB is wrong about hard water. Your water hardness is fine and within proper balance.
Why wasn't the two inches below the tile acid treated?
But the PB is wrong about hard water. Your water hardness is fine and within proper balance.
Why wasn't the two inches below the tile acid treated?
Yeah, we're waiting to see if the discoloration comes back in a month or so. My wife and I agreed that if it doesn't come back after 6 months, we'll do an acid wash of the entire pool before the next season. If it comes back, no point in doing the acid wash.
I read some other threads on here and they talk about "hydration stains", where too much water was between the gunite and plaster during the plastering (they did my plaster on a somewhat rainy day though they used a tarp), so the water leeches through the plaster and out into the pool. During this leeching process, the stains and discoloration are visible, but they go away over time as all the water is leeched out when the plaster is finished curing. Has this been true in your experience, at least in some cases?
Don't know why they didn't treat the top 2 inches...
ppm is the same as mg/L (for practical purposes because the density of the water is very nearly 1 g/ml). 151 mg/L is the same as 8.82 grains/gallon. This is Total Hardness so includes magnesium. Typical water has around 70% of Total Hardness being Calcium Hardness so you can figure the CH of your fill water perhaps being around 106 ppm.
"Hydration stains or discoloration" is a misnomer, and misunderstood. Once new plaster is submerged in water, it is always saturated with water. The plaster surface doesn't dry out, but does continue to hydrate and harden over time.
Therefore, it is true the normal (non-severe) and typical plaster mottling (cloudy, but not gray) will slowly even out and lighten in color over several years.
Therefore, it is true the normal (non-severe) and typical plaster mottling (cloudy, but not gray) will slowly even out and lighten in color over several years.
I've been really interested in this thread! I have mottling, white streaks and my CH is 800. Mr. PB, plasterers, and plaster co. Rep have all been out. All attributed it to high PH and hard water. After showing them my log of testing and adding acid every other day they just shook their heads. The plaster rep told me that the color we have is no longer on their website and they do not recommend it for exactly the problem we are seeing. Had Mr. PB informed me of that I sure wouldn't have chosen it. Good luck - I hope your PB does the right thing!
I'm thinking of getting the National Plasterer Council involved, too. I'll have the plaster sample tested, and when the results come back, I'll try to get the NPC to come and visit, too.
FWIW, my fill water has a CH of only 125 (close to chem geek's estimate), but it's TA is through the roof at 190. pH is around 8.0.
Also noting my pH and TA jumped significantly after the spa's acid wash... went up to 7.7-7.8, and TA jumped to 100 from 80. Added MA to bring those back down.
Also noting my pH and TA jumped significantly after the spa's acid wash... went up to 7.7-7.8, and TA jumped to 100 from 80. Added MA to bring those back down.
Update to this thread:
Got a plaster sample tested, and the calcium chloride content was 2.7%... over the allowable 2% (and 0-1% that my PB claimed). In a sense, I feel relief in knowing exactly what the problem was, and encouraging that I'm doing nothing wrong with the water chemistry. But I'm also ****** at the PB.
Got a plaster sample tested, and the calcium chloride content was 2.7%... over the allowable 2% (and 0-1% that my PB claimed). In a sense, I feel relief in knowing exactly what the problem was, and encouraging that I'm doing nothing wrong with the water chemistry. But I'm also ****** at the PB.
Please share what he says. This is very interesting.
I bet they did not treat the area in the spa right under the tiles as they did not want to mess with taping off the tiles to protect them.
Kim
I bet they did not treat the area in the spa right under the tiles as they did not want to mess with taping off the tiles to protect them.
Kim
Another update:
PB verbally agreed to replaster once he saw the test results! They acknowledged the mistake and promised to "make this right". A stand up man of his word, this guy I talked to
My attention turns to how to ensure a proper plaster job and a proper start up...
PB verbally agreed to replaster once he saw the test results! They acknowledged the mistake and promised to "make this right". A stand up man of his word, this guy I talked to
My attention turns to how to ensure a proper plaster job and a proper start up...
Congratulations!
I am glad you made the effort to get a resolution. This should provide others an understanding of the process and what can happen.
And kudos to your pool builder for understanding and doing the right thing.
See this post on proper plastering. http://www.troublefreepool.com/threads/41414-Ten-Guidelines-for-Quality-Pool-Plaster
I am glad you made the effort to get a resolution. This should provide others an understanding of the process and what can happen.
And kudos to your pool builder for understanding and doing the right thing.
See this post on proper plastering. http://www.troublefreepool.com/threads/41414-Ten-Guidelines-for-Quality-Pool-Plaster
