Not All Color Pigments are Good for Pools

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
974
Utah
There are two important issues involved when trying to achieve quality colored pool plaster that will remain durable, attractive, and the proper shade for many years.

The first issue is to utilize superior workmanship practices to achieve good color, with minimal mottling, and no blotchiness, white streaking or soft spotting, which our previous email update addressed. (Note: Some pool owners prefer the slight mottling variation that is normal for colored plaster).

The second issue is using quality color pigments (added to plaster mixes) that will hold up well for years and not lose its’ color in a swimming pool environment, which is the topic of this update. One would think that all color pigments used in pools are colorfast, meaning that the color doesn’t fade or become bleached in chlorinated water or in sunlight. Sadly, that is not the case.

What has been learned?

The onBalance team has conducted many experiments with various pool plaster products, such as pebble and quartz exposed aggregate products that contain color pigments.

It appears the plaster products that contain “organic” pigments become bleached (loss of color) over time when subjected to chlorine (an oxidizer). But products with “inorganic” pigments generally do not become bleached. Additionally, experiments which subjected both organic and inorganic pigments to LSI aggressive water showed that neither type of pigment lost their color from etching.

When an organic pigment, phthalo blue for example, is bleached and loses its color over time in chlorinated water, the plaster surface becomes “whitish” because it is made with white Portland cement.

However, it was also observed that when two (or more) color pigments are added to a plaster product mix to obtain a unique and special color, and the blue organic pigment became bleached and faded, the other color pigment(s), if inorganic and colorfast (often a gray or brown pigment), remains unaffected, intact, and becomes the dominate color.

Obviously, only pigments that are colorfast are appropriate for swimming pool finishes.

Question: Why would material manufacturers and plasterers sell and use non-colorfast pigments that will not keep their color? One reason may be that organic (non-colorfast) pigments are usually much cheaper than the superior (colorfast) inorganic pigments. Of course, that allows some companies to underbid the quality-oriented companies.

Who Takes Responsibility or Not

The NPC has a Technical Bulletin addressing common color pigment problems. Amazingly, their bulletin does not mention anything regarding colorfastness and that (organic) color pigments can be bleached by chlorine or other oxidizers. Plus, no acknowledgement that excessive water troweling can cause white streaking, soft spotting, or blotchiness to slowly develop over time. And no mention that calcium chloride (hardening accelerator additive) should not be used with colored pigments as manufacturers WARN against, as it also contributes to severe blotchiness.

Instead, the NPC suggests that “aggressive water” causes color fading or whitening of colored plaster (along with causing many other plaster defects and discolorations), all of which is false. Of course, calcium scaling can mask the color, but that can be easily determined and rectified.

The plaster industry has misled the industry that water chemistry has the most significant and negative effect on the durability and color of plaster. To the contrary, there are various plaster/cement studies that have shown that poor workmanship and materials have a greater effect.

Think about this: Plasterers and material manufacturers generally recommend performing extremely aggressive “acid bath” or “hot start” treatments on new plaster and exposed aggregate finishes to accentuate the color or to remedy some discolorations. If those acid treatments aren’t causing plaster defects or discolorations, then on what basis do they claim that slightly aggressive water during Start-ups or afterwards causes all unsightly plaster problems?

Bottom Line: Using quality materials, including colorfast pigments, and superior workmanship will best ensure a durable and attractive pool finish for 20 years or more. That is what my father’s plastering company provided for their customers.
See this link for information on proper plastering practices. Ten Guidelines for Quality Pool Plaster

For photos of bleached pigmented plaster and more detailed information, click on these two links:

Pigments and Pools | Pools/Spas | Watershapes

http://www.poolhelp.com/wp-content/uploads/2017/01/Colorfastness-Handout.pdf
 
Last edited:

CaveDiver1932

Well-known member
Mar 2, 2014
98
Dallas
@onBalance

1) From your handout referenced above, the first sample - It appears to have blue pebbles in the top half, but the bottom half has none. Was the blue pebble broadcast onto the surface after applying the finish or is this a different sample?

2) what colors can you get that are inorganic?

3) how and what do you request from the applicator to get inorganic color additives instead of the organic additives?


Thanks
Cd
 

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
974
Utah
1) The first sample was obtained from the supplier and cut in half. Therefore, the pebble's colors are the same on both halves.
2) Cobalt blue is inorganic and much more expensive than the phthalo blue pigment. Iron oxide is a good black color.
3) You simply insist that any and all color pigments are colorfast and preferably inorganic and to warranty their product. Of course, the best thing to do is to do your home work, inspect the color pigments prior to the job, and ensure that they are appropriate and colorfast to chlorine.
 
Last edited:

CaveDiver1932

Well-known member
Mar 2, 2014
98
Dallas
Thanks. Did you have the sample in hand? Why I ask, manufacturers ask for a premium for blue pebbles. If they bleach, there is no benefit to addition of blue pebbles.
 

Leebo

Admin
TFP Expert
LifeTime Supporter
Jul 21, 2011
8,900
Eastern Ohio
Kim, great writeup!

So is it commonly known which colors are made from organic dyes verses inorganic or is it something that the builder will look at you clueless when you ask?
 

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
974
Utah
Lee, good question.
I do not know what builders know and don't know. Some builders probably do not know anything about colorfast issues. They are probably simply trusting the manufacturers of premix cement/aggregate/pebble products or the sub-contractor plastering company they hire to provide the appropriate plaster materials. And those two groups may not know about colorfastness. Both of those groups probably purchase color pigments (or dyes) from the pigment manufacturers and don't ask which is which. And are they willing to pay the higher price for the inorganic and colorfast pigment? If they do know the difference, are they going to admit that they provided a color product that doesn't hold up in chlorinated water? Often, they don't. Blaming the water chemistry has become an easy (but incorrect) target.

I believe there is one manufacturer of premix plaster products (including quartz, pebble) that advertise that they use only "inorganic" color pigments. My hat is off to them.
 

CaveDiver1932

Well-known member
Mar 2, 2014
98
Dallas
@onBalance - On the flip side.. the NPC has published a technical bulitin that dances around .. alludes to water chemistry.

https://www.npconline.org/resource/resmgr/technical_library/techbull4/tech_bulletin_4_-_the_most_c.pdf

Now, the NPC states “For swimming pools, the greatest potential for pigment masking is on newly installed finishes within the first 3-days after the pool is filled with water. Adhering to a proper start-up procedure is important. Removal of any calcium hydroxide that migrates to the surface (plaster dust) is also important. ”

In their startup guide
“Due to unique local water conditions and environmental factors, parts of these recommended start-up procedures may need to be modified to protect the pool finish. For example: filling the pool with extremely low calcium hardness, low pH or low total alkalinity levels may necessitate changes to these procedures.“

However, the NPC does not state what or how to make these changes. Furthermore, when pressing a NPC technical member that is involved in teaching startup procedures, what process is followed for such for fill water, etc, nothing is provided.

Not to mention the acid wash done to pebble prior to water fill 🤯. No mentions...

It’s disappointing that the NPC defaults to water chemistry ie. pool owners fault for any issues to pool finishes. Further, the “recommended” ideal chemistry ranges are not realistic. Not only that, following their startup trashes the pool surface (their tech bulletin) during the fill process. Even if their findings are true, then why don’t they demand improvement in materials? Isn’t that their charter?

As for warranty of product, that almost seems comical.. NPC has provided a process of exculsions backed by third parties. OnBalance, have you found any plasterer that provides such?

Cd
 
Last edited:

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
974
Utah
Cd, I agree with your assessment that the NPC Tech bulletin is contradictory and/or inconsistent and falsely points the finger at water chemistry for plaster discoloration. They claim that the first three days of water balance is most important, but yet, the NPC permits the plaster contractor to fill the new pool with aggressive water. That comprises the first day or two that the water is not balanced, and yet, they don't site that as leading to discoloration problems. They only blame the service tech or pool owner when discoloration problems occur. And as you know, I have shown that the filling of new plaster with aggressive tap water leads to the dissolving of a lot of plaster material (calcium hydroxide) from the plaster surface. That in turn, raises the calcium and alkalinity level of the water before the start-up person shows up. So on what basis does the NPC blame the start-up person for not balancing the water? That is clearly baseless. Yet, that is the norm.

Another good point you raise is that many new color plaster and quartz finishes receive an acid treatment of some sort before or immediately after filling. Yet, they don't mention that as leading to any plaster problems. That is evidence that aggressive water doesn't cause plaster discoloration and should point to improper plaster practices as the cause. But they continue to ignore that evidence. All of this demonstrates how baseless their position is. Service techs and pool owners are being victimized unfairly.

In my opinion, there is no excuse that the NPC's Tech bulletin does not mention or address colorfast issues and the problems with using organic color pigments. This only enables the bad plasterers to not take responsibility for poor workmanship or using inappropriate materials.

And as you mentioned, their agenda is apparent when they mandate perfect water chemistry maintenance for service techs and pool owners to follow, and then blame all plaster problems on the water balance.

I am aware of some good plastering companies that believe in performing good practices and using appropriate and more costly materials. They take their time and do not speed through the plastering process. And they stand behind their work. They do not like what the NPC is doing.
 
Last edited:

CaveDiver1932

Well-known member
Mar 2, 2014
98
Dallas
@onBalance,
1. Can you share a picture of the backside of the before and after pebble non-colorfast samples? It would help in determining what the white Portland cement with pigment fades to when subjected to chlorine. For example if a black pigment is added to make a light or dark grey, would it tuned a lighter gray color or an unpleasant tarnish color?
2. Pigments/dyes - a consumer would expect / or be led to believe that when they purchase a name brand product like Pebble Tec, Stone Scapes ,etc the manufacture’s pigment would be used, however it appears plasterer’s can use their own/third party pigments. For the pool owners/pool maintainers your organization consulted, where you able to determine if the manufactures pigment was used?
3. The majority of the plasterers seem to exclude color plaster/cement pebble from warranty even if proper extreme limiting NPC chemistry standards are maintained. Perhaps this was in response to the outcome of your work with these pool maintainer’s insurance companies cross claims to plasterer’s faulty workmanship/materials?
4. I suspect if a consumer inquires about pigments, the responses will vary and most likely be either the pebble manufacture does not make the pigments and use the highest quality pigments available..followed with all color pigments are going to fade because of water chemistry.

And..
E0E7FE31-5593-4B53-836C-D75B5CB71555.jpeg

Thanks
Cd
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
15,859
Tucson, AZ
Difference is key - NPC is an industry organization beholden to its members, ie, plastering companies. It owes its existence to them and therefore its allegiance is to their bottom-lines. They will write the standards that benefits their members and that’s not necessarily in the service of scientific principle or public good. If plasterers were more closely regulated by a government chartered organization, then there would be a slightly better chance of standards being developed based on hard facts and not member-interests.

All the consumer can do is study, ask tough questions and get the best results possible from the available supply of plaster applicators. Trying to fight these issues after-the-fact through the warranty process is a money losing & time wasting proposition for the pool owner. Only the cases of the most severely gross negligence will be addressed quickly; everything else will simply be a war of attrition.

Thank you @onBalance for these great briefs on plaster application. They will be referenced for years to come ...
 

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
974
Utah
Thank you Matt.

Cd, I will try to address your questions.
1) We glued Velcro pads on the back of those coupons. If you look at the photos in the Watershapes article, a couple of them show how the blue color only pigment turns almost completely white after bleaching. Other photo samples show the blue color completely disappearing and leaving the gray or brown pigment. My experience with black organic pigments is that they also turn almost completely white.

2) We obtained the plaster/aggregate coupons samples directly from the name-brand manufacturers, not from pool owners or service techs.

3) The NPC wrote their "color disclaimer" many years ago, long before we released our findings a couple of years ago.

If you are inclined, you can come to the Western Pool & Spa Show this year and see our coupon samples in person. You can also obtain your own coupon samples from the manufacturers and perform your own bleaching test and personally see the results.
 

pewl

Well-known member
Aug 3, 2018
88
Coastal SoCal
@onBalance , I have been reading many of your articles and find them all very helpful! This week we should be plastering our new pool. We are planning on using standard plaster, no aggregate finishes. Our PB told me it would come from NPT, but also said the color and plaster would be mixed on-site, not premixed. In your Watershapes article "Pigments and Pools" it is stated that blue pigments seem to be more problematic than grays. I know to only allow inorganic pigments to be used in my pool, but my PB is unfamiliar with this topic and I will not meet the plaster guys until plaster day- only communication is what I ask my PB to find out from them. I've tried to find out if NPT pigments or other brand name pigments are inorganic or not but it seems like impossible information to find!
Can you tell me a specific brand or brands of acceptable inorganic pigments? Is there an acceptable blue inorganic pigment you could tell me the brand name of? I know one of your sample coupons in your study was an inorganic blue that proved to be colorfast. I'd love to have a very specific brand/color name to request they purchase for my pool. Thank you so much!
 

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
974
Utah
Ask for "cobalt" blue pigment which is inorganic. I prefer not to discuss brands.
Since they will be mixing on site, you can look at the pigment packages and learn what brand and type of color pigment it will be.
 
  • Like
Reactions: Don_TLR

pewl

Well-known member
Aug 3, 2018
88
Coastal SoCal
Ask for "cobalt" blue pigment which is inorganic. I prefer not to discuss brands.
Since they will be mixing on site, you can look at the pigment packages and learn what brand and type of color pigment it will be.
Thank you @onBalance . I will do that. I heard from the PB today that his plaster company told him they use NPT Plasterscapes. Fingers crossed their blues are cobalt based. I am having the hardest time finding that information online.
 

tampatommy

Well-known member
May 2, 2017
258
Tampa, FL
Hey onBalance, are "Mineral based pigments" considered inorganic or colorfast? The dye bottles from NPT for stonescapes have "Mineral based pigments" listed on the label.
 

CaveDiver1932

Well-known member
Mar 2, 2014
98
Dallas
Hey onBalance, are "Mineral based pigments" considered inorganic or colorfast? The dye bottles from NPT for stonescapes have "Mineral based pigments" listed on the label.
Generally minerals are considered inorganic. In this instance most likely synthetic.
Also note, it’s is also probable that a particular plasterer would use a third party pigment instead of the pebble manufacturer’s pigment for various reasons
 
  • Like
Reactions: tampatommy

QueHales

Member
Nov 24, 2017
8
Tucson, AZ
Also keep in mind that the blue that most commonly fails is called "copper phthalo blue." So that particular pigment may be mineral (metal) "based" (the copper) but it definitely IS NOT colorfast to bleach... which makes it even more important if YOU are on the hook for the finish, to pre-test a sample or take a look at the MSDS.