As many pool professionals know, the first 28 days after a pool has been plastered — or replastered — are critical in determining the quality of the surface.

If done properly, plaster jobs can hold up for decades, and are even capable of undergoing acid washes or the occasional bout of aggressive water. But plaster that’s treated carelessly or incorrectly may etch and degrade, and may never recover.

But what exactly constitutes a proper start-up? The question has spurred years of debate, and the industry as a whole has yet to reach any real consensus. Still, research has yielded some helpful insights, and pool start-up technicians have coalesced into a few major “schools.”

Some continue to use the slightly alkaline “traditional” start-up, some support an acidic start-up, and a few keep their water pH-neutral. And perhaps no debate in the plaster field has been more prolonged and contested than that between supporters of the National Plasterers Council start-up and the “bicarb” method advocated by onBalance, a group of service technicians who perform independent research on plaster and water chemistry.

But a recent Pool & Spa News survey revealed some interesting wrinkles. Even those plasterers and servicepeople who argue for a particular start-up method tend to apply their own variations, and many have developed specialized methods for different surfaces. Here, we explore some of these innovations, and examine the popularity of each major start-up method in regions across the country.

Different strokes

The broad category of “plaster” isn’t just one single type of interior finish — it may be a traditional or colored mix, a pebbled surface, or an exposed aggregate surface containing quartz, seashells or other substances. While some plasterers and servicepeople stand by their start-up method regardless of the surface, some say these various finishes look and feel superior when treated with a slightly different chemical regimen.

Many plastering companies acid-wash aggregate surfaces as soon as the surface has dried — usually the day after application has been completed.

Some go so far as to run the pool’s circulation system at a low pH for several days. “For the first week, I’ll drop the pH to 6.0 or below, so the water’s acidic and it exposes the quartz or the pebbles or whatever it is in the finish, and evens the surface out,” says Scott Schmitz, project manager at All American Custom Pools & Spas, a Pool & Spa News Top Builder in Norwalk, Conn. “Then, by the second week, we’re bringing it back up to normal.” At that point, Schmitz’s techs start balancing other factors in the water, such as calcium hardness and total alkalinity.

Still, many experienced servicepeople caution that any acidity beyond an initial wash can prove dangerous to the plaster’s integrity. “Acid start-ups have a tendency to create etching,” says Jim Meadows, former owner of Meadows Plastering in Tucson, Ariz.

Meadows, like many plasterers and techs throughout the country, stopped using the acid start-up when he noticed that acid-treated surfaces tended to degrade in the long term. Scientific examinations of plaster subjected to an acid start-up have confirmed that even smooth-seeming surfaces acquire microscopic etching when started up this way. Thus, in recent years, the acid start-up has slowly faded as a preferred method, while others have gained in popularity.

Divergent emphases

Regardless of whether the pool surface receives an initial acid wash, plasterers and servicepeople agree that it’s crucial to protect the plaster’s integrity as it hydrates and matures. Just how one ought to go about this, though, is a subject of debate. The majority of techs and plasterers surveyed have aligned themselves with the position of either the NPC or onBalance.

The main difference between their methods is what they emphasize as most important. The NPC method focuses on “ideal” ranges for factors in the Langelier Saturation Index, maintaining that if all LSI values are in their ideal ranges, and the LSI itself is a slightly positive value (between 0.0 and +0.3), the water will neither scale nor etch the surface — and that simple chemical adjustments on each service visit are sufficient to maintain balanced water. During the start-up process, the NPC encourages techs to brush the surface regularly to remove plaster dust (carbonated calcium hydroxide, also known as calcium carbonate), leaving a smooth surface that loses none of its strength.

This method has long been disputed by onBalance: Though its members agree that the NPC’s ideal ranges are unlikely to etch or scale a surface, the group takes the position that plaster dust can — and should — be prevented entirely if possible. Thus, onBalance maintains that if tap water is soft or aggressive, then vulnerable new plaster is best protected during the filling process by introducing sodium bicarbonate (“bicarb”) into the tap water, keeping the water so saturated (+0.5 to +1.0 LSI) that it has no tendency to dissolve plaster dust out of the surface. In other words, onBalance’s position is that it’s better to prevent aggressive tap water coming into contact with new plaster altogether, especially during the first few days.

This, onBalance says, will result in a smoother, stronger surface than one treated with other start-up methods. However, the onBalance method requires the water’s alkalinity and LSI values to be lowered to within a normal range after 28 days, making this method more time- and equipment-intensive than the NPC start-up.

Both groups have supporters across the country. For some, loyalty to their method of choice seems to eliminate the desire to understand the opposing method — or the reasons for opposing it — in great detail.

Innovations and variations

In spite of general support for one method, many say these approaches may not be appropriate or practical under all circumstances. Thus, these techs have composed their own variations.

Those who support the bicarb start-up, for example, explain that while this method might be ideal, it’s not realistic in every situation. The method — as described by onBalance — requires a large barrel to be filled with sodium bicarbonate, which runs slowly into the pool through a series of hoses. This barrel begins to dilute the bicarbonate into the tap water as soon as the filling process starts. It then requires daily refills and adjustments, which some techs say aren’t always reasonable to expect of a homeowner, and are impractical for a busy service company.

Another common concern is that builders or plasterers may not call in a service tech to start the bicarb process before the pool is already filled. “It’s difficult to get the equipment on-site within a few hours of the start of filling, and to get a tech to the job site in time,” says Jerry Wallace, president of Swim Chem in Sacramento, Calif.

Thus, some techs have developed a “delayed” version of the bicarb start-up that works for them. “Our adaptation is to dilute the bicarb with water and distribute it into the pool after the water’s reached the tile line,” says Mike Bunker, owner of Ace Pool Service in Visalia, Calif. This gives him or his techs a few extra days to make it to a job site, and still allows him to maintain the method’s required level of bicarb.

Others have found that environmental factors affect the usefulness of the bicarb method. “Bicarb works best in warmer weather,” says Troy Becker, owner of Ojai Pool Store in Ojai, Calif. During the winter months, Becker may use the bicarb method, but he finds that more residual alkalinity tends to accumulate in the pool. “So we’ll immediately start working with acid and brush vacuums the first day after fill, to get that bicarb out of the water,” he says.

Meanwhile, some advocates of the NPC method have adapted its ranges for the water chemistry of their regions. “I keep the pH a little lower than normal at first,” Schmitz says, “because it tends to drift upwards.”

Rather than calculating the LSI, Schmitz mainly pays attention to pH, bringing the other factors into their ideal ranges once he’s able to maintain a chemical equilibrium between the plaster and water. “We do things piece-by-piece, starting with pH and building off of that,” he says.

As all this demonstrates, there’s no single start-up method that works without fail, on every surface, in every climate, with every range of source water chemistry. Only by experimenting, keeping careful records and sharing data can the industry hope to develop start-up methodologies with wider applicability and greater reliability.

“Everyone’s still working toward the perfect start-up,” Becker says. “We’ve got to educate ourselves, do proper testing, and base our decisions on the data we gather.”