Re-plastered pool continues to produce erotion spots

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Kim,
Responses integrated below prefaced with a '>'

I forgot to tell you my name is Kim, and I am a former pool plasterer many years ago.
> Thanks Kim for the introduction

Pool sand or aggregate is an off-white color. I think the fact that the smooth plaster part is gone indicates an advanced stage of this erosion problem.
> As I look at the entire pool, the erosion is predominately on the left side of the pool. The steps seem to be the worse, but the problem seems to be progressing rather than subsiding, even though all chemistry measurements are with acceptable ranges. Of course it doesn't make the pool unusable, but the rough patches can scuff up the skin

Were the spots smooth when first noticed and now are more rough to the touch?
> The spot starts out generally with a small discoloration. When I feel one that is starting it feels different (maybe slightly rougher) but only where the discoloration is.

I would think that the spotting would have been visible within the first year. Yes, no?
> I didn't notice the spots until about a year and a half or so. Of course just after the warranty had ended.

I am hoping that you have some records to show that you informed the plasterer at the beginning of all this.
> well in May of 2008 a few months after the re-plastering was done, I had them come out to look at brown speck marks which unfortunately was rust marks from an old heater. During that visit, they did do water testing of which they recorded on the copy of the sheet they left me. It shows that the Ph was about 8 but all other measurements were within acceptable levels. Additionally, CYA readings (if they were taken) were not documented as are referenced in the letter at the bottom.

I am curious what state you are located in, but some states have a contractor's license board that you could contact and ask for an inspection.
> I live in California in the San Francisco Bay area west side.

I can provide some literature to you that would help inform the agent if he isn't familiar with this problem. I have worked with some CA and AZ agents in the past.
> I appreciate any information you can send me and would be happy to send you my personal email address for that. You make reference to 'agents' and I assume you are referring to contractors/inspectors?

Essentially, the spots can be caused by a combination of things and the degree of abuse. First, the plasterer usually adds too much calcium chloride to the mix, then the plaster hardens too fast and they splash water onto the surface to soften up the plaster which weakens certain areas of the plaster surface. Then over time, deterioration takes place and (balanced) water will dissolve the weak and soft cement material (back into the pool water) causing increased porosity of those areas or spots.

Interestingly, your plaster does not look like a lot of calcium chloride was added, but that doesn't change the final outcome if true.
> Can you tell me what you are looking for in the plaster to conclude that it had Calcium chloride abuse?
> Can you also tell me what the reasonable range for CYA is? Bioguard testing results shows it to be 30-200 and Leslies show it to be 30-99. In any cases I have never exceeded 90.

>As I was responding to your questions, I received a response from the refinisher which essentially tries to negate my concerns. The enclosure that was sent with it came from http://www.poolspanews.com/2008/052/052acid.html The letter states as follows:
Re: Plaster staining
John,
We once again visited your pool. Again we found the cynauric acid level to be high (90). Last year in August we saw the pool, offered to drain and repair the plaster. Because we needed to sand the finish we could not guarantee that there would be an even color once done. This was not the first time we visited your pool, as far back as May of 2008 we saw and talked to you about your chemical readings.
Stains and improper maintenance are not covered under warranty. You claim that you have been taking your water into a pool company to have it tested and they recommend higher levels of cynauric acid than the pool industry and the National Pool Plasters Council. This is not your personal fault that the pool company who checks your chemicals does not adhere to industrial standards.
However we have three times tried to offer help. Keep in mind what you have had happen is not caused by the plaster. The last time we have had this happen was in the mid 80's when stabilizers became popular and this problem began to occur. I have enclosed an article in regards to cynauric acid problems.
You state in your last letter of October 3, 2011 that you made the right decision not to have us drain and repair the pool. Unfortunately this problem that you find yourself in now could have been averted if you had let us drain the pool, sanded the pool, refilled with new water, and you followed our advice. The only way to stop the staining would have been new water and rebalancing the pool. At this juncture the pool is no longer repairable.
 
I remember the article. I also remember the Arch sponsored test paper. It wasn't worth the paper it was written on, as I recall. Little details like using fresh plaster and pouring the CYA directly on the test tablets and uncirculated, unbalanced water kinda blew that report out of the water.

Given the time of year and geo of the pool, I would say the most likely cause was re-wetting during application. If bisulfate was used to lower the pH during the cure and it wasn't brushed, and only only on flat surfaces and the pool went unbrushed and uncirculated, then I "might" have reason to believe this was an owner based issue.

The fact that it's on walls too kills the above paragraph's potential other causes. Plasterers almost always tell the pool owner how to care for curing plaster. Some of the basics of that care are brushing frequently and don't start adding any balancing chems except muriatic acid or, in the case of the "high alk startup", baking soda.

I find it more likely that the plaster was mixed in batches that exceeded the finisher's ability to properly trowel it on a timely basis. That the pH was high would cause scaling and not spot etching is significant.

Scott
 
Johngee,
From the pictures, the unaffected areas of your plaster doesn't seem to have a slightly "gray" color. It seems to be fairly white. That is why I don't think an excessive amount of calcium chloride was added. But I could be wrong, and your pictures may not show it very well.

The APSP set the minimum and maximum CYA at 10 to 100 ppm. That is THE standard, not what the NPC states.

I like what PoolGuyNJ said about the cyanuric acid study conducted by Arch. It is a flawed study with many problems.

But for now, let's just address the refinisher's (plasterer's) position. The Arch study only suggests that a high CYA content can cause uniform degradation, and as PGNJ stated, the water was unbalanced and aggressive per the Saturation Index. They did not compensate the high CYA (150 ppm - 500 ppm) with a higher TA. But for your issue, the important point is that the Arch study did not claim, suggest, or say ANYTHING about a high CYA causing "spotting" that your plaster has developed. So I would ask your refinisher; Where in that study proves or claims that a CYA level of 70 to 90 ppm causes any damage, and where in that study states that a high CYA causes "deteriorated spotting" while leaving the rest of the plaster surface smooth and unaffected? Of course, the answer is that the study doesn't make either claim.

Lastly, I believe California law says that if any workmanship is deemed to defective, then the warranty is more than just one year. Check it out.
I think it might be beneficial to agree for the refinisher to drain and "sand" the spotted areas. It may have a slightly different color contrast, but if he can get the surface smooth, then the plaster will look better than it does now, and should last a long time. But I think an acid wash would be a mistake. However, if he does a good job of sanding, then perhaps a very light acid wash would be okay to remove any dirt or metal stains and even out the overall color. But that is a tough call.
 
What was that offer? Did they want to be paid? How come you didn't have them re-plaster then?
> Good question -Answer: because they wanted to charge me $1000 to sand and patch. And I was afraid from what I had been observing that after having that done would not stop the plaster degradation. In addition, I got no assurances that doing so would not halt the process. So I spend another $1k, refill and balance at my expense, and get no further assurances the problem won’t continue, just that matching color would be almost impossible. I’m glad I didn’t because from my perspective I would have spent that money, had a patchy appearance, and still have further plaster degradation. There has never been an offer to re-plaster, just patch.

John
 
John,
I'm sorry, I thought they were offering to sand your pool for free as a PR gesture, as they should. That was the basis for suggesting to take them up on their offer. But not if they are charging for it.
I think you should "push" a little and maybe they will do it for free. Don't forget about about the CSLB.
BTW, tell the plasterer that for over 30 years, thousands of pools across the country have had CyA levels of 100 ppm and didn't result in spotting erosion. I bet he has looked at pools with 100 ppm of CyA that didn't have any plaster issues, including spotting.
 
Kim,
>You said in a previous posting that:
I can provide some literature to you that would help inform the agent if he isn't familiar with this problem. I have worked with some CA and AZ agents in the past.
> Would it be possible for you to send me that literature, and if appropriate, names of agents you may know in Calif.> I suspect I'll need to contact them.
>Also, you are right about the law in California. It is called Latent Defect in Construction, and it is good for 10 years from construction finish date. I think I see you saying that I should get my ducks in order as I may need to lean on this law.
John
 
Question about CSLB.
If I were to contact them, would it be a reasonable request to have an inspector come out and do an inspection? Does there need to be any litigation in place before I request an inspector?
John
 
Southern Cal is where a few CSLB agents have learned about this problem. Don't know any in Northern Cal. As far as I know, you can ask for an inspection without any litigation in place. They also have hearings to render a verdict.
Goggle "spot etching (and soft spotting) plaster pools." It appears you are going in the right direction if you want resolution.
 
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