Carbonates are the traditional buffering system used in swimming pools. They perform the vital task of keeping the pH from fluctuating, thus ensuring the water in the pool remains comfortable for bathers and doesn't attack the vessel that contains it. They've been doing it well for years, and their market penetration is, in the opinion of Jeff Lloyd, about 100 percent.
Lloyd is vice president of research and development for Nisus Corporation, a chemical company in Rockford, Tenn., that makes a borate buffering system. Borates, though far less common than carbonates, perform a similar buffering function — and provide some extra benefits that carbonates can't, he says.
But what's left for borates in a world where all the buffer business has been spoken for?
"Right now, they're not considered competing materials at all," Lloyd explains. "Virtually every pool in the United States has a carbonate system. Test strips or chemistry tests look for that with total alkalinity. Borates definitely do not have that market presence. They're not sold against carbonates, but rather for other benefits — additional buffering, performance as an algeastat and increasing the chlorine performance."
Still, Lloyd recognizes that Nisus and other borate makers face a stiff challenge from the better-known and ubiquitous buffers. After almost 30 years in the borate business, though, he's confident more pool owners and service professionals will soon see what he sees in this miracle metalloid.
High And Low
"Anyone who's been in the industry understands that carbonate alkalinity is typically what we use to help buffer pH," explains Karen Rigsby, technical services senior specialist for BioGuard Pool and Spa Products, Lawrenceville, Ga. "Carbonates typically work at a little bit lower pH and borates typically work at a higher pH. So if you have both of these in the water it works really, really well to help you stabilize and maintain your pH."
Maintaining a pool's pH in the 7.4 to 7.8 range is crucial, because, for one thing, if it gets higher than that, the sanitizer becomes less effective.
"If you have a pH higher than 7.8, all of the chlorine is present in the water as hypochlorite ion, and the hypochlorite ion is not a good sanitizer," Lloyd says. "It's hypochlorous acid that's a good sanitizer.
"But by having the pH in the right area, you have a nice balance between hypochlorinte ion, to keep the chlorine in the water, and hypochlorous acid to kill the bugs. So that's really what you're trying to do."
High pH can also lead to issues with calcium not dissolving properly, a problem that manifests itself in cloudy water and scaling.
"At a very high pH you can also get some skin sensitivity and eye sensitivity," Lloyd adds. "But it's the human exposure to pathogenic bacteria that's of primary concern. That's the reason we have sanitizers in the pool in the first place."
Keeping the pH from sinking into acidic ranges is equally important.
"If your pH gets too low, the chlorine becomes really reactive and disappears very quickly," Rigsby explains. "So keeping your pH in the right range is going to make your water not only look and feel better, it's going to help your sanitizer work better, too."
Water with a low pH can also cause soreness and redness in the eyes, skin irritation and problems with the pool itself as the water becomes aggressive and eats away at the lime in the gunite.
One reason for Lloyd's enthusiasm for the future of borates in the marketplace stems from the product's past, which he describes as something of a qualified success.
"The early borate formulations were very similar in chemistry to the old Borax product," he explains. "The chemical is sodium tetraborate pentahydrate. It works very well after it's fully dissolved and you re-neutralize the swimming pool. But because it's a granular, crystalline product, it can be quite difficult to dissolve."
He and his team of scientists have come up with a new liquid formulation of borate that he says solves that problem, though the idea that granular borates are a problem in the first place is not a universal one.
Like Lloyd, Rigsby is wont to sing the praises of borate's ability to buffer pool water, provide water that's smooth on the skin and easy on the eyes and can even control algae (more on that later). But she doesn't see the granular formulation BioGuard and other manufacturers use to be much of an issue.
"Any of these products, once you dump them into the water, are going to behave similarly," says Rigsby. "So it's just a matter of what is convenient for people to use."
BioGuard's borate, Optimizer Plus, is broadcast into the pool, where it will dissolve then get to work. Asked about the possibility of the product clumping on the bottom of the pool, or, worse yet, being sucked in through a skimmer and binding the pump, Rigsby has some simple answers.
"You don't put this in the skimmer. Aside from chlorine tablets, I don't ever recommend that people put other things into the skimmer," she says. "And we don't recommend that anyone dump it onto the surface of a pool, because it's got a high pH and could cause surface damage. If it does fall to the bottom in a single spot, though, you just brush it up."
Another issue Lloyd has with granular borate formulations is their alkalinity, which approaches 9.5, necessitating the addition of acid to bring it back to earth.
"So what you have to do is to acidify the pool again, to take that pool from pH 9.5 back down to about 7.6 in order to make the chlorine work efficiently again and sanitize and kill potentially pathogenic bacteria," he says. "And because it's such a strong buffer, you have to add a lot of acid."
The new Nisus formula takes this step out by starting out with a lower-pH form of borate, then acidifying that down to an acceptable level, according to Lloyd.
"What we did is instead of starting with a sodium tetraborate pentahydrate, which has a very high pH, we start with another borate material, which is disodium octoborate tetrahydrate, which has a pH of about 8.5, then we acidify that and concentrate it," he says.
"Really what we're doing in terms of chemistry is we've essentially just got less sodium in the formulation," he explains. "The sodium tetraborate has a lot of sodium, and obviously sodium hydroxide, which pool professionals are very familiar with, makes it very basic. So we remove nearly all of the sodium hydroxide so now we've got a nice, stable-pH material.
"When you add it to the pool it adjusts the pH of the water to 7.6. You don't need to add more acid."
BioGuard's Optimizer Plus has a pH of 9.3, and Rigsby says users need to add about one pound of pH decreaser (acid) for every two pounds of the granular product. This is a little extra work, but in light of the treatment's longevity, not a significant issue, according to Rigsby.
"Once you add the Optimizer Plus and the pH increaser and your pH is in the right range, you don't have to keep adjusting it, unless you get a lot of rain and your pH gets off," she says. "In that case you'd need to make some small adjustments."
On that makers of both granular and liquid formulations of borates can agree. Once they're in the pool, they stay in the pool.
"Unlike most other pool water additives, the borate is permanent and does not degrade or evaporate from the water with time," Lloyd says. "A single dose application will only need very minor topping off, perhaps one a year."
What About Algae?
When discussing borate's role as relates to algae, Rigsby and Lloyd are careful to point out that it's not a biocide and, while it's got a lot to recommend its use, it doesn't do a good job of killing things. The key to its effectiveness lies in the way it helps the sanitizer kill algae by keeping the pH in proper range.
"At higher concentrations, though, borates can act as a biostat, meaning it will prevent the growth of the organisms," Lloyd explains. "Borates stop the algal cell from both producing food (photosynthesis) and then eating it (metabolism)."
"Also, the water just looks better," Rigsby says. "People comment on how it adds a bit of sparkle and clears the water. Do you have to use it? Of course not. You can absolutely maintain the pool without it. But the water will look and feel better and be easier to maintain, so why wouldn't you?"
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