According to the latest working draft of the Model Aquatic Health Code, there’s no reason for indoor pools to use cyanuric acid, even in products such as dichlor and trichlor.

Though the code is currently a work in progress and thus open to comments and revisions, some in the industry are concerned about the implications of such a restriction.

“If a pool service guy can’t throw a tablet in the skimmer, he’s going to have to come back to the site twice a week to maintain that pool’s chlorine residual,” said George Verbryck, technical director at AlertCorp, a chemical compliance firm based in Long Beach, Calif. “I don’t think a lot of service companies have the personnel to sustain that.”

The proper use of cyanuric acid (CYA) has been a point of controversy for more than a decade. Experts agree that CYA is effective at protecting chlorine from breaking down under the sun’s ultraviolet radiation. But a sizable body of evidence also suggests  that, particularly in high concentrations, the chemical may inhibit chlorine’s disinfection capability. And because CYA itself doesn’t break down in water, that concentration tends to rise over time as dichlor or trichlor tabs are added to the pool.

These concerns prompted the Centers for Disease Control and Prevention earlier this year to recommend against CYA use in indoor pools and spas in the most recent draft of the MAHC.

“We know there’s very strong data showing that cyanurates weaken the disinfection capacity of chlorine,” said Michael Beach, associate director for healthy water at the CDC in Atlanta. “So, since they were originally intended to work in sunlight conditions, we don’t see any reason that they should be used in an indoor aquatic facility.”

But such clear-cut views aren’t shared by all. “Has enough science been published for the CDC to decide with certainty what the best decision about cyanuric acid is? Probably not,” said Tom Lachocki, CEO of the National Swimming Pool Foundation in Colorado Springs,Colo. “But you do have to give them credit for using a body of peer-reviewed scholarly publications to guide their decision.”

It isn’t just published research that will shape the final code, Beach said. The CDC is counting on public comments to inform the ongoing drafting process. Thus, he encourages interested parties to visit the CDC’s Website at, and submit their views for or against any point of the proposal.

Verbryck, however, isn’t convinced that individual comments will hold much weight. “We need to band together as an industry, meet amongst ourselves, and share our concerns with a unified voice,” he said.

A draft of the full MAHC has yet to be assembled from the series of modules currently under 60-day review.

“This is a public document; we’re working with people from across the country on this,” Beach said. “We know there are a lot of different viewpoints on this, so we want to make sure we hear from everyone.”