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.
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…Continue
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 automatically…Continue
Added by Kim Skinner on February 6, 2019 at 4:24pm — No Comments
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).
Added by Kim Skinner on January 17, 2019 at 3:30pm — No Comments
The Art of Good Pool Plaster Color
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.
One of the primary reasons for non-uniformity is that pool plaster a hand-finished product. It is…Continue
Added by Kim Skinner on January 17, 2019 at 3:25pm — No Comments
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.
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.
However, one plaster industry leader suggests that even when pool water is LSI balanced, if the…Continue
Added by Kim Skinner on October 12, 2018 at 3:36pm — No Comments
Orenda Technologies has recently unveiled a new start-up program that prevents the formation of plaster dust by adding calcium (calcium chloride) to low calcium tap water while filling brand-new plaster pools. We have received communications asking us if this calcium program is compatible with, or a viable alternative to the Bicarbonate Start-up Method that also prevents plaster dust.
The Orenda start-up program can, in certain situations, be an effective alternative to the Bicarb…Continue
For pool builders, remodeling companies, and pool plasterers that want the best chance to obtain a quality and discoloration-free pool plaster finish (including white, color, and quartz aggregate pools), the link below is to an article in WaterShapes (a pool industry publication) that explains the preparations, workmanship, and practices to follow.
Consider performing personal supervision on the entire process to ensure good results.…
Beginning in 2004, a series of plaster research studies were released by the National Plasterers Council (NPC), which they instigated and financially supported, and which were undertaken by the California Polytechnic State University in San Louis Obispo. In these studies, the researchers concluded that aggressive water conditions were the cause of “spot etching” and other plaster surface defects. The conclusions, and the quality of the research, have long been contested within the industry,…Continue
It appears that the pool industry’s long-time recommended parameters for chlorine and pH levels will be changing in the near future.
The current range of 1 to 4 ppm for chlorine will likely be raised when pool water contains cyanuric acid (CYA), and the pH range will be broadened beyond the current limited range of 7.2 to 7.8. The reason for this change is due to a new understanding of the science of stabilized pool water.
Some years ago, Richard Falk (known as Chemgeek on pool…Continue
The research and consulting group onBalance has decided to conduct new plaster research studies to generate additional evidence regarding the cause of unsightly plaster discolorations and defects. The plaster issues of concern are gray mottling discoloration of white plaster, white spotting of both colored and white plaster, calcium nodules, spalling, flaking, and craze-cracking.
One aspect of the study will be to construct two demonstration pools, each with sections of various…Continue
Added by Kim Skinner on March 23, 2017 at 3:29pm — No Comments
For at least 40 years, many pool service companies have been successfully maintaining their residential pools on a once-a-week visitation basis. Empirical evidence has shown that pool water can be kept safe and properly sanitized without harmful bacteria and algae developing with weekly treatment programs.
Also, pool service companies provide a great service by keeping hazardous chemicals out of the hands of pool owners and their children.
One reason that pools can be kept…Continue
It is amazing how incorrect information gets started, and gains traction despite being wrong, and not based on science. For example, contrary to some pool literature and manuals, it has been shown that a pH of 8.0 to 8.4 is workable, and sometimes is best for some pools.
Another misconception regarding pool water maintenance involves the recommended “Ideal” alkalinity range of 80 to 120 ppm. While that may be a good range for some pool situations, it is not necessarily the best when…Continue
Added by Kim Skinner on September 13, 2016 at 3:33pm — No Comments
Experienced service techs know that the pH in many of their pools generally rises above 7.8 within four to seven days following chemical treatments. It is a chemistry reality that when water contains 80 ppm to 120 ppm of carbonate alkalinity, and is left alone and untreated by additional chemicals, the pH will rise to 8.0, and sometimes as high as 8.4 and stay there until chemically treated again.
What does this mean? It means that thousands upon thousands of residential pools are…Continue
Some plasterers are occasionally finishing pools so fast that it detrimentally affects the quality and durability of plaster surfaces, and are not even aware of the consequences. And the NPC is enabling for this to happen. This needs to stop. Improper practices can speed up the finishing process, but they also lead to a short life-span for plaster, lasting only five-ten years instead of twenty. They are not doing the consuming public right by condoning, and by omission endorsing, those…Continue
Added by Kim Skinner on February 24, 2016 at 2:25pm — No Comments
Imagine, service techs: from day one, you maintain the pool water in perfect balance, yet get blamed for causing various plaster discolorations or defects. That is not a pleasant thing to deal with, especially if you are being told to pay thousands of dollars to re-plaster the pool.
Yes, some plastered pools (including quartz and pebble finishes) may develop either white spotting and streaking, calcium nodules, gray mottling discoloration, spalling (flaking), severe craze (check)…Continue
The swimming pool publication, Service Industry News and its’ PhD chemist, recently peer reviewed the NPC/Cal Poly (NPIRC) Phase 2 pool plaster study report and concluded that white spotting (soft spots, spot etching, and spot alteration) of their plaster pools was not caused by aggressive water, and that the claims (by the NPC) regarding that study are false. In fact, every plaster study of the past twenty-five years has exposed that the NPC is wrong, and that aggressive pool water does not…Continue
Added by Kim Skinner on September 18, 2015 at 6:00pm — No Comments
If NPC leaders would just acknowledge what improper plastering practices do to pool plaster, there would not be a controversy within the industry - and there would be fewer plaster defects and discolorations occurring.
Case in point: Adding calcium chloride (hardening accelerator) to plaster and water troweling enables pools to be plastered faster and easier. But adding calcium chloride (CC) to a color pigmented plaster can also lead to blotchiness and mottling, which pigment…Continue
Added by Kim Skinner on September 3, 2015 at 10:30am — No Comments
Instead of writing a “he said, she said” article about the plaster spotting controversy, Service Industry News (SIN) thought it would better serve the pool industry by conducting their own investigation to determine what information is true, and false. They started on that goal by analyzing the Cal Poly test pool studies. In their July 31, 2015 issue, SIN presented credible evidence (from the Cal Poly Phase 2 report) that the white spotting of the plaster test pools was not caused by…Continue
The NPC has drafted a plastering standard which has been submitted to ANSI for approval. But the NPC did not include and address many proper and improper workmanship practices, such as, limiting water content (water-to-cement ratio), calcium chloride additions, and wet (water) troweling. These are all very important issues for the making of quality pool plaster.
And unfortunately, an article by Pool & Spa News about the new proposed plaster standard does not tell the whole story…Continue
Decades ago, people in the pool industry started becoming aware that there was more to pool maintenance than just adding sanitizers to the water (to kill algae and bacteria) and filtering it (to help keep it crystal clear). Gradually, we learned that even properly sanitized and filtered pool water could become unbalanced.
We figured out that unbalanced water could be either scale-forming, in which case a layer of calcium scale would form everywhere – or…Continue
Added by Kim Skinner on April 20, 2015 at 10:43am — No Comments