lsi - Articles - Pool Genius Network2024-03-28T20:12:39Zhttps://poolgeniusnetwork.com/blog-1/feed/tag/lsiPlaster Finishes Should Last 20 Yearshttps://poolgeniusnetwork.com/blog-1/plaster-finishes-should-last-20-years2019-02-12T00:07:10.000Z2019-02-12T00:07:10.000ZKim Skinnerhttps://poolgeniusnetwork.com/members/KimSkinner<div><p>All pool plaster finishes should last 20 years or more. However, some last only 5 to 7 years, and some less than a year before the plaster surface deteriorates, discolors, and looks terrible.</p>
<p>Why the difference? Very often, plaster quality. As we have pointed out previously, studies on pool plaster and cement/concrete flatwork have shown that poor workmanship practices have the greatest effect on durability, deterioration and discolorations. Various studies also confirm that water chemistry plays only a minor role.</p>
<p>Fortunately, there are a lot of quality plasterers that understand the importance of proper plastering, and generally take an extra hour or two to properly plaster pools with good materials and good workmanship practices. Their pools usually last 20+ years.</p>
<p>However, there are some poor-quality plasterers that are in a hurry and use inferior and “short-cut” practices and/or materials to plaster quickly. Doing so allows them to underbid the quality plastering companies. Their pools usually last less than 5 years, and sometimes less than a year before the plaster problems begin. And when the plaster finish starts looking bad, they simply blame the water chemistry instead of their own sloppy workmanship. Sadly, they are enabled to do that by the NPC and APSP.</p>
<p><strong>A “Pretend” Plastering Standard</strong></p>
<p>A few years ago, the NPC and APSP got together to write an ANSI plaster standard. Unfortunately, they refused to mention and include important and critical workmanship requirements (well known by the cement and concrete industry) that would produce quality, durable, and discoloration-free plaster/cement finishes. No limits or standards at all!</p>
<p>Furthermore, the APSP/NPC standard doesn’t mention the defects, deteriorations, or discolorations that can result due to improper and inferior workmanship. That means there is no accountability for plasterers that do poor work. Sounds like a “protection” standard. Pool builders and State Contractor License Boards have little recourse to help pool owners.</p>
<p><strong>What about Water Chemistry Standards?</strong></p>
<p>On the other hand, APSP and NPC have very strict and narrow standards for pool water maintenance. Beyond that, their literature (incorrectly) suggests that if pool water is not maintained within their suggested water parameters, that plaster problems will result. No, in reality plaster studies show that slightly aggressive LSI water does not cause the defects or discolorations at issue.</p>
<p>The NPC and APSP should not be exaggerating and misusing the importance of proper water balance which leads to service techs and pool owners being incorrectly blamed for many different plaster problems.</p>
<p>Obviously, poor water chemical maintenance can result in uniform etching and/or scaling. Even some types of metal staining can be traced to chemical mismanagement. However, when plasterers attempt to associate spotting, streaking, mottling, discoloration of the paste, calcium nodules, spalling, etc. to water chemistry causes, you know there is no basis for that. They are factually known to be caused by improper materials, application or curing failures.</p>
<p><strong>The Bottom Line</strong></p>
<p>APSP and NPC should rewrite the ANSI Plaster standard and adopt applicable workmanship standards (similar to ACI and PCA standards) to promote durable and discoloration-free plaster finishes for pool owners. That would serve the industry much better and help prevent plaster problems occurring in the first place.</p>
<p>However, this ongoing travesty probably won’t change until the entire pool industry becomes informed of these issues, rejects the false claims that water balance is what causes the above plaster problems, and demands that the NPC and APSP make things right.</p>
<p><strong>Addendum:</strong></p>
<p>When a plaster finish develops discoloration or defects, the following questions should be asked.</p>
<p>What does adding too much water, or too much calcium chloride (hardening accelerator), or performing too much water troweling, or overly late and excessive hard troweling do to plaster finishes? </p>
<p>And wouldn’t “tenting” pools (to overcome harsh weather conditions) and taking an extra hour help to produce a higher-quality plaster finish?</p>
<p>Those are the important issues that are missing from the APSP/NPC/ANSI Plaster Standard.</p>
<p>The following links provide additional details regarding these issues.</p>
<p><a href="https://watershapes.com/professional-watershaping/a-plastering-watch-list.html">https://watershapes.com/professional-watershaping/a-plastering-watch-list.html</a></p>
<p><a href="http://www.poolhelp.com/ten-steps-to-durable-and-discoloration-free-plaster/">http://www.poolhelp.com/ten-steps-to-durable-and-discoloration-free-plaster/</a></p>
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<p><em>Comments and questions are welcomed.</em></p></div>Is Pool Water Balance Always the Problem?https://poolgeniusnetwork.com/blog-1/is-pool-water-balance-always-the-problem2019-02-06T23:24:22.000Z2019-02-06T23:24:22.000ZKim Skinnerhttps://poolgeniusnetwork.com/members/KimSkinner<div><p>For 50 years, the pool industry has considered pool water within an LSI of -0.3 and +0.5 to be acceptable and balanced. But recently, and without providing any supporting science or research, the NPC is trying to convince the industry that any negative LSI (-0.1 to -0.3) is unacceptable and immediately detrimental to pool plaster. Their theory also suggests that an alkalinity below 80 ppm, or a low calcium level (below 200 ppm) independently as being <strong><em>automatically</em></strong> aggressive even if the LSI is positive.</p>
<p>It is also being claimed that those water conditions cause gray mottling (of white plaster), craze cracking, variable white blotchiness and streaking of colored plaster, random calcium nodules, and plaster flaking (spalling) to occur in just a few weeks or months. That is all nonsense.</p>
<p><strong>Contradictions to Those Claims</strong></p>
<p>Let’s consider that plaster consultants recommend adding 8 to 10 gallons of acid to a 20,000-gallon pool for one week to improve the aesthetic appearance of new plaster finishes, including quartz and pebble. That acid treatment (or acid start-ups, now disingenuously referred to as “hot start-ups” by plasterers) lowers the pH to about 3.5, the alkalinity to a negative number (below zero), and the LSI to -4.0. That water is about 5,000 times more aggressive than an LSI of -0.3. If that type of water doesn’t cause the above plaster issues, how then could water that is 5,000 times less aggressive do that?</p>
<p>Plaster experiments show that those acid treatments dissolve and etch up to 30 pounds of calcium material from the plaster surface and, assuming the surface is relatively of consistent quality, do so uniformly without causing discoloration. (btw, the total weight of plaster material in a 20,000-gallon pool is about 4000 pounds).</p>
<p>In comparison, maintaining an LSI of -0.3 for six months may dissolve about 1.5 pounds of calcium material. In other words, it takes at least 10 years of consistently maintaining an LSI of -0.3 to equal the same uniform etching effect of adding 10 gallons of acid for one week. Note: It is very difficult to constantly maintain a negative LSI because aggressive water seeks to balance itself as it liberates calcium from the plaster surface, and the pH generally rises.</p>
<p><strong>More Contradictions</strong></p>
<p>The NPC/Cal Poly (NPIRC) plaster study was used to mislead the industry regarding aggressive water chemistry. Reviews by two Ph.D. chemists indicated that the (fabricated) conclusions don’t match the results and data. Those studies actually demonstrated that deterioration and spotted discoloration occurred in balanced (non-aggressive) water and in only four months. That implicates poor workmanship or materials as the problem, not aggressive water.</p>
<p>The Portland Cement Association and the American Concrete Institute do not blame rain (aggressive water) for causing rapid discolorations and defects on cement/concrete surfaces. Instead, they have identified improper workmanship and material issues as causes. Rain is about 1,000 times more aggressive than an LSI of -0.3 (which occurs often in pools), and yet, does not cause similar defects or discolorations (as mentioned above) on cement sidewalks and driveways, even after several years.</p>
<p>For many years, thousands of pools across the country have been intentionally (and unintentionally) maintained with slightly aggressive water to prevent calcium scaling, and they do not develop plaster discolorations or defects.</p>
<p>There are petrographic (forensic) plaster studies showing that improper and <strong>“short-cut”</strong> practices cause plaster discoloration and deterioration problems, some of which only become visible after pools are filled, and sometimes even after months. See this link: <a href="http://www.poolhelp.com/home/onbalance-research/consulting/">http://www.poolhelp.com/home/onbalance-research/consulting/</a></p>
<p><strong>The Bottom Line</strong></p>
<p>Maintaining slightly aggressive water (LSI -0.1 to -0.3) is acceptable. It does not cause rapid plaster deterioration and discolorations problems on quality applied pool plaster. The plaster problems mentioned above are prevented by following good workmanship standards. Right now, there are none. Good standards would provide accountability, slow down the plastering process, and give pool owners a quality and beautiful plaster finish that lasts 20 years.</p>
<p> </p></div>Are All Color Pigments Good for Pool Plasterhttps://poolgeniusnetwork.com/blog-1/are-all-color-pigments-good-for-pool-plaster2019-01-17T22:30:06.000Z2019-01-17T22:30:06.000ZKim Skinnerhttps://poolgeniusnetwork.com/members/KimSkinner<div><p>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.</p>
<p>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).</p>
<p>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.</p>
<p><strong>What has been learned?</strong></p>
<p>The onBalance team has conducted many experiments with various pool plaster products, such as pebble and quartz exposed aggregate products that contain color pigments.</p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>Obviously, only pigments that are colorfast are appropriate for swimming pool finishes.</p>
<p>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.</p>
<p><strong>Who Takes Responsibility or Not</strong></p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>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?</p>
<p><strong>Bottom Line:</strong> 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.</p>
<p>For photos of bleached pigmented plaster and more detailed information, click on these two links:</p>
<p><a href="https://watershapes.com/pools-spas/pigments-and-pools.html">https://watershapes.com/pools-spas/pigments-and-pools.html</a></p>
<p><a href="http://www.poolhelp.com/wp-content/uploads/2017/01/Colorfastness-Handout.pdf">http://www.poolhelp.com/wp-content/uploads/2017/01/Colorfastness-Handout.pdf</a></p>
<p> </p></div>The Art of Good Pool Plaster Colorhttps://poolgeniusnetwork.com/blog-1/the-art-of-good-pool-plaster-color2019-01-17T22:25:13.000Z2019-01-17T22:25:13.000ZKim Skinnerhttps://poolgeniusnetwork.com/members/KimSkinner<div><p><strong>The Art of Good Pool Plaster Color</strong></p>
<p>An attractive plaster color (other than white) is often preferred by pool owners. However, it is very difficult for plasterers to produce a uniform and consistent color. The reality is that there will always be some minor shading (mottling) and variation in the color and can never be uniform looking like paint or fiberglass.</p>
<p>One of the primary reasons for non-uniformity is that pool plaster a hand-finished product. It is plastered by multiple finishers and subjected to a variable environment during curing. Most pools are also plastered using multiple batches of material which will never match precisely.</p>
<p>Pool owners need to accept that reality. In fact, the National Plasterers Council (NPC) appropriately recommends that a “Disclaimer or Waiver” be provided to pool owners to explain that there may be slight differences in the color shading.</p>
<p>Fortunately, quality-oriented plaster companies know how to produce a relatively good-looking color finish that will satisfy most pool owners. Along with other good practices, such as tenting pools to control temperature and humidity, they use colorfast pigments, a low and consistent water/cement ratio in all batches of material, they do not add any calcium chloride and do not add water to the surface during the troweling process. Lastly, they achieve a smooth finish with a properly-timed final troweling before the plaster becomes too stiff.</p>
<p><strong>When the Color goes Bad</strong></p>
<p>Obviously, poor chemical maintenance can either etch or scale any surface, including colored surfaces, but those are known and accepted phenomena. There are two non-chemical reasons for color problems developing with new plaster finishes, including quartz and pebble finishes. They are workmanship and materials.</p>
<p>When a pool is plastered too fast, due to adding too much calcium chloride set accelerant, the plaster surface can display severe and irregular mottling, color fading, or white blotchiness, streaking, and spotting. Also, if other quality workmanship practices, such as proper troweling, trowel pass timing, water/cement ratio, refraining from wet troweling or propane torching, etc. are not followed, increased negative effects may plague the surface aesthetics. And understand that those ugly discoloration problems generally take a few months to worsen and become increasingly visible.</p>
<p>Of course, a “Disclaimer or Waiver” document should be not used as an excuse by plasterers to avoid taking responsibility for their work quality.</p>
<p>The above discoloration issues are not caused by aggressive water. If it did, then colored cement driveways and walls (on buildings) would have similar results when rained upon (which is aggressive water). Yet, they do not because they are usually applied properly.</p>
<p>On other hand, overly positive LSI pool water can cause calcium scaling and can mask the colored plaster with a whitish deposit. When that happens, acid (<em>aggressive water</em>) treatments are often performed to remove the white discoloration and darken the plaster color again. Also, many quartz and pebble companies recommend maintaining the pool water slightly (LSI) aggressive to prevent the general whitening process from occurring altogether.</p>
<p>Therefore, aggressive water cannot be the cause when it removes the “white discoloration” and darkens the plaster color. And there are no plaster studies showing that slightly (LSI) aggressive pool water causes irregular white blotchiness, splotches, or streaking in colored (or white) plaster pools to appear in just a few months.</p>
<p>Evidence from plaster/cement petrographic “forensics” studies show the cause and effect relationships between color surface failure and improper workmanship practices. See this link for reports on this topic. <a href="http://www.poolhelp.com/home/onbalance-research/consulting/">http://www.poolhelp.com/home/onbalance-research/consulting/</a></p>
<p><strong>The Bottom Line</strong></p>
<p>Good workmanship standards are needed for the pool plastering trade.</p>
<p><a href="{{#staticFileLink}}3423451578,original{{/staticFileLink}}" target="_blank"><img class="align-full" src="{{#staticFileLink}}3423451578,original{{/staticFileLink}}" alt="3423451578?profile=original" /></a></p></div>The LSI is Reliablehttps://poolgeniusnetwork.com/blog-1/the-lsi-is-reliable2018-10-12T22:36:53.000Z2018-10-12T22:36:53.000ZKim Skinnerhttps://poolgeniusnetwork.com/members/KimSkinner<div><p>Using the Langelier Saturation Index as a guide for maintaining proper pool water balance and to protect pool plaster has become a mainstay in our industry, and we believe, for good reason.</p>
<p>We at onBalance have conducted several LSI experiments and have determined that maintaining a balanced LSI (-0.3 to +0.5) helps prevents scaling and prevent the etching of plaster finishes.</p>
<p>However, one plaster industry leader suggests that even when pool water is LSI balanced, if the alkalinity level is below 80 ppm (the industry’s Ideal minimum, not Operating minimum, which is 60), the pool water is aggressive and can discolor or damage pool plaster. Not so.</p>
<p>Anyone that is experienced in calculating the LSI knows that a low alkalinity can be offset by raising the calcium level and/or raising pH to keep the water balanced. To demonstrate and confirm that, we conducted several plaster experiments.</p>
<p>For example, two quality pool plaster coupons were made and cured in balanced water for 30 days. At that point, one coupon was placed into water that had a low Total Alkalinity of 40 ppm, well below the minimum standard. The Calcium level was set at 350 ppm and the pH was maintained from 7.8 to 8.0, which off-set the low alkalinity and achieved a balanced LSI of about -0.1 to +0.1.</p>
<p>The other plaster coupon was placed into water with a low Total Calcium level of 90 ppm. The alkalinity was maintained at 130 ppm and the pH from 7.8 to 8.2, which together off-set the low calcium level and achieved a balanced LSI of about -0.1 to +0.3.</p>
<p>After six months in the water, the plaster coupons were removed from the water containers, and the water was tested for the calcium content to determine if any dissolution and etching of plaster surface material occurred. (An increase in calcium from the water’s starting point would indicate that calcium had been dissolved from the plaster coupon, which contains the only available source of calcium in this experimental set-up).</p>
<p>The result? There was zero increase calcium in either water container.</p>
<p>The results of this experiment are totally consistent with the concept of calcium carbonate saturation as published in the municipal water supply, as well as the swimming pool chemistry industries. The results demonstrate that even when the alkalinity or calcium level is low – below the APSP’s minimum standard – but the LSI calculation shows that the water is balanced, then the water IS balanced, and therefore, not aggressive. But understand, we aren’t recommending that maintaining low alkalinity or calcium hardness levels is the preferred way. This is just information to help pool builders and service techs confront false claims about water chemistry and various plaster problems.</p>
<p><strong>The False Claim Regarding Aggressive Water</strong></p>
<p>It is very unfortunate when new pool plaster surfaces sometime develop either gray mottling, white spotting and streaking discoloration, flaking (spalling), craze cracks, calcium nodules (from delamination), or other such defects, all of which are attributable to poor plastering workmanship, and yet, instead of advising the plastering company that improper plastering practices occurred, one NPC inspector (incorrectly) tells pool builders, service techs, and pool owners that aggressive water causes the above problems.</p>
<p>As mentioned above, the blame is often directed at low alkalinity or calcium hardness levels even though the actual LSI was balanced! But more importantly, the above listed plaster problems are NOT caused by aggressive water. Cement literature, empirical evidence, and even the NPC/Cal Poly/NPIRC study results demonstrate that.</p>
<p>Even when pool water IS aggressive, and etches plaster, it etches it <strong>uniformly,</strong> not in a mottled, spotted, or streaked pattern unless the plaster is non-uniformly defective as well.</p>
<p>It is our hope that pool builders, service techs, and pool owners will not be fooled by such non-sense. But it is happening far too often. Members of the onBalance team are often contacted regarding plaster problems, and we try our best to help them avoid being a victim of false claims.</p>
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