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
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
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 www.cdc.gov, 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.”