A frequently made mistake in the use of automatic controllers takes
place on the commercial side.
When it comes to commercial pools and spas, health codes often
dictate that automated controllers be calibrated with a test kit to
make sure the unit is correctly monitoring the chemistry levels.
But it’s easy for conscientious operators to become
“You might have three people in a day looking at a chemical
controller and calibrating it to a test-kit reading,” says
Ron Akin, vice president of sales at Santa Barbara Control
Systems in Santa Barbara, Calif. “The problem with that
is at different times of the day and with different people looking
at the same test results, you’re going to see different
These conflicting readings may cause multiple users to constantly
adjust the controllers, even when there may not be anything
“The tendency to overcalibrate the unit can be a problem
because people are overriding what the sensor itself is
saying,” Akin says. “Although it should be checked, if
it’s within the margin of error of the accuracy of the probe,
we really don’t recommend overcalibrating the
Akin recommends that calibration occur at the same time each day,
so that usage and lighting conditions are more consistent, and the
results will look as similar as possible. It’s also best if
the fewest people possible calibrate it, to minimize conflicting
translations of the results.
“As long as you’re within the health department’s
accepted realm of what your low and what your high is, and if
you’re around your set point, you really should kind of let
the controller operate with as little interference as
possible,” he says.
If the unit must be calibrated more often than normal and a cause
can’t be found, it is best to call the manufacturer. There
may be a problem with the sensor or controller.