The pool and spa industry’s research and consulting team, onBalance, is at it again with an exciting new study that aims to determine the causes of bleaching in what were originally brilliantly-colored plastered pools.
It’s the second study in as many years that the group has undertaken with their demo pools located in Tucson, Arizona, which they built with the help of industry professionals to get to the bottom of a variety of pool and spa mysteries. (Their first experiment investigated drain-free cyanuric acid removal).
This year, they’re looking at studying the colorfastness of blue pool plaster pigments.
“Pool owners have been long disappointed with the fading of the blue color in their pools,” said onBalance’s Kim Skinner.
Skinner says that pool surfaces that were initially vibrant shades of blue routinely turn gray and lifeless over time. For this reason, he says, many plasterers have discontinued plastering with blue pigments, or only in conjunction with exposed aggregates that disguise the blue-togray color shift. Meanwhile, other plasterers have blamed the color loss on improper (aggressive) water chemical balance, Skinner says. onBalance has experimented with pigmented plaster color loss in their lab and has investigated the literature. They believe they have determined that the primary cause of color loss in blue-pigmented plaster is the use of organic pigments, which are bleachable. These are commonly used in the pool industry.
The results of their laboratory experiments have shown that plaster pigment distributors provide both colorfast inorganic blues (usually cobalt-based) and bleachable organic blues (usually copper phthalo-based) to the pool plastering industry.
“Inorganic, colorfast blues are much more expensive, but do not bleach,” said onBalance’s Que Hales. “The better distributors freely disclose whether the blue pigments they sell are colorfast in a pool environment.
But others do not. We have consulted in cases where pool service companies have been blamed for color loss when it was not their fault.” So onBalance has designed a simple experiment that should, once and for all, get to the bottom of the issue.
They’re using two of their demo pools, and they are plastering each with four separate pigmented plaster combinations that are readily available and specifically sold for use in the swimming pool plastering industry.
Section one of each pool will be plastered using organic copper phthalo blue pigment. Section two will be plastered using the very common combination of organic copper phthalo blended with an inorganic gray. Section three will be the same as section two, but with calcium chloride set accelerant also added. Section four will be plastered using inorganic cobalt pigment.
After plastering, one pool will be maintained with balanced water chemistry, and the other with aggressive water chemistry. The pools will then be maintained in those conditions until the bleaching (or lack of bleaching) is evident.
“We’d like to invite members of the industry to come by and view the pools as the project unfolds, to compare colors, to doublecheck water chemistry, and to learn with us,” said Hales.
More information is available on their website at www.poolhelp.com.
onBalance demonstrating that calcium hardness can be removed without draining by using soda ash and a D.E. filter.
