Most pool professionals can tell you how ozone stacks up against traditional sanitizers such as chlorine and bromine.
But many don’t know how to properly operate and maintain the
ozonator on a residential pool.
“It’s tricky because there are a lot of different
systems out there,” says R.J. Marozzi, owner of Gourmet Water
Systems in Westlake Village, Calif. “The pool guy walks in
and thinks, ‘What am I supposed to do with this
Ozonators produce ozone either through ultraviolet light or corona
discharge. Each unit may have a distinct set of manufacturer
recommendations for plumbing and maintenance.
When servicing an ozonator, it’s important to first orient
yourself to the system, its installation and basic features. Though
upkeep is minimal, routine maintenance is key to preserving the
life of the unit. Finally, make sure the water is balanced for the
ideal application of ozone.
Learn the system
When it comes to ozone systems, a technician must be able to
recognize a correct installation and know the expected output for
If servicing a pool with an ozonator, start by consulting the
unit’s manufacturer about its specific features and
operation. You’ll also need to know the unit’s on/off
procedures, particularly when it comes time to winterize the
Begin by inspecting a few common problem areas.
The heater: Check to make sure the ozonator and
heater were not plumbed in direct succession. If an ozonator is
installed just before the heater, the ozone may oxidize and damage
the copper heat exchanger. Conversely, by placing the heater just
prior to the ozonator, there’s a risk that the hotter water
will slow down ozone oxidation.
Back pressure: This can push water into the unit
and severely damage the ozonator. A check valve generally will
prevent water from backing up into the equipment.
However, because check valves wear out over time, it’s a good
idea to take extra protective measures. Back pressure can be
reduced by using larger eyeball fittings on the return line,
assuming the ozonator doesn’t have a separate return. You
also may reduce the number of fittings.
Power: If done incorrectly, simply turning the
system on or off can damage the unit. On return-side ozonators with
a venturi injector, for instance, running the ozonator without the
pump on can cause major damage to the unit.
Chad Relis, service manager at Clearwater Tech in San Luis Obispo,
Calif., says it’s vital to disconnect the ozonator during
“If the pool is winterized and you shut everything down, but
still run water through [the system] so it doesn’t freeze,
you’ll kill [the unit] if you don’t disconnect the
tubing,” he explains.
Ozone output: It’s important to understand
how much ozone a pool requires, and for how long. While the unit
produces a certain amount of ozone, a ball valve at the injector
will determine the rate at which it’s introduced to the
water. A corresponding gauge on the unit tells how much ozone is
being delivered to the pool.
As such, always keep the filter clean. As pressure builds, the
amount of suction will change, altering the ozone output. If you
don’t clean the filter, eventually there won’t be
sufficient oxidation to clean the pool.
Often, a service tech will pick up an account with an ozonator
already properly installed. The tech now must replace worn parts
and ensure the unit works correctly.
The manufacturer will have a short list of maintenance procedures,
but in general, keep an eye on fan screens, high-wear parts and
Fans: An ozonator unit often has a fan to cool the
unit and prevent it from overheating. If the ozonator you’re
servicing has a fan, check for a screen or filter, which can become
clogged with dirt and debris and must be cleaned.
“It’s actually the most important thing guys can do
because [otherwise the units] overheat and can’t get air to
cool them, so we get circuitry problems,” Marozzi says.
Screens can be cleaned and rinsed in the pool; then they should be
set out to dry for three to four minutes.
Screens should be checked on a monthly basis, Marozzi adds.
Parts replacement: Higher-wear parts should be
replaced every year or so. For some units, this could mean changing
out O-rings or desiccant cartridges. Check with the manufacturer
More generally, most ozonators should be outfitted with new tubing
and check valves each year.
On outdoor installations, the unit’s clear vinyl tubing is
constantly exposed to the sun. The tubing then will degrade,
becoming yellow and brittle, and eventually crack. Though a vacuum
system should prevent gas leaks, the ozone won’t be able to
enter the circulation system.
Check valves may deteriorate as well; they should be replaced,
along with the tubing, each year.
Electrode or bulb life: Corona discharge
electrodes and UV bulbs are rated for a certain number of hours. CD
electrodes generally last longer than UV bulbs, but both should
last several years, varying by manufacturer and daily use. UV
bulbs, however, will have a diminished effect over time.
Replacement is relatively painless and shouldn’t take more
than a few minutes, according to Rick Taylor, a sales manager at
San Luis Obispo, Calif. based DEL Ozone. Just be sure not to touch
the UV bulb with your fingers because it could affect performance.
As always, consult the manufacturer for replacement parts and
Warning signs: Many ozonator units include
indicator lights that display current operating status and report
ozone leaks. But a seasoned tech can detect other problems simply
by observing the unit.
“There are certain sounds to listen for when something is
wrong — like if a fan’s going out, the bearings will
become loud and make funny noises,” Marozzi says.
For example, on a larger unit for a commercial pool, a broken
oxygen concentrator will make a loud, continuous popping noise from
inside the unit, he adds.
Correct water chemistry
A pool with an ozonator must be properly balanced.
Industry-recommended levels for pH and total alkalinity should be
But there are a few more things to watch for. Chlorine is now a
supplemental oxidizer and should be introduced in smaller doses.
Also, high TDS and hardness levels must be monitored because they
can clog the injector.
Chlorine levels: Typically, chlorine is used as a
residual sanitizer. Because ozone quickly leaves the main body of
water, chlorine remains to fight any newly introduced contaminants.
It’s particularly useful in oxidizing material that’s
stuck to the pool wall.
However, maintaining 2- to 3 ppm of chlorine in the pool can be
wasteful. The higher the chlorine level, the more likely that ozone
will transform the chlorine to ineffective chloride ions. Instead,
Relis recommends keeping between a 0.5- and 1 ppm level of chlorine
to avoid complications.
Similarly, in-line chlorinators and ozonators can work against one
another. The two systems should be kept separate and introduced at
different stages in the circulation system.
Keep the injector clean. A venturi injector won’t get clogged
in a pool with good water chemistry, provided the ozonator is
correctly installed after the filter.
However, high levels of calcium can cause buildup where the ozone
and water come together inside the injector.
This reduces ozone output — and may prevent the pool from
effectively oxidizing contaminants. You can test for poor vacuum
draw with a flow meter where the tubing connects to the ozonator
unit. If the draw is poor and there’s no obstruction in the
tubing, there’s probably buildup.
If the injector becomes clogged, some manufacturers recommend
disconnecting the tubing and injector from the unit, and cleaning
them with vinegar or a muriatic acid solution.
Soaking the tubing and injector for a few hours should clear out
any mineral deposits.
If there’s a high hardness level, a chelating agent can help
prevent material buildup.
How Ozone is Made
Oxygen molecules (O2) split by adding energy or UV
light, resulting in two individual oxygen atoms (O1).
Oxygen atoms (O1) unite with other oxygen
molecules (O2) to produce ozone (O3).
(O1) + (O2) = (O3)