Wireless, Web Based CAT 4000 Automated pH/ORP Water
Chemistry Controller.

"ORP is the bottom line. Get it, somehow; it is necessary to make your water safe and to keep it safe."
Professional Pool Operators of America. www.ppoa.org

None of the water we checked showed any signs of bacteria.
Jamie's not surprised.
"Most of the Clark County (Municipal) pools have a very
automated system, so whenever a chemical gets out of range,
they have constant testing to let them know when something is
going wrong without having a pool operator out here testing
throughout the day."
Jamie Hubert SNHD inspector as quoted on NEWS 3.
"The popularity of recreational water venues, the number and the
resistance of Cryptosporidium to chlorination suggest that
treatment strategies for recreational water facilities need to be
. CDC RWI Report 7/27/2007
We installed our first automated water chemistry controller in
the summer of 2006. This was on an apartment pool that
was frequently closed due to excessive bather load resulting
in turbid (cloudy) water.

In the two years since the controller was installed:

       The pool has not been closed once due to
cloudy water.

       100% safer, saved thousands of gallons of
water, and did not pollute the environment with
excessive chemicals & by-products.

      The water chemistry has been checked and data
logged every minute, 24 hours a day, seven days a
week, 365 days a year.

       We have made zero repairs on the controller.
(Routine maintenance & cleaning of the probes &
chemical pumps only).
Westside Pool CAT System Installed on Pool
June 2006
Westside &  Automated Water Chemistry
Why Automated Controllers?
For most apartment complexes we service, the swimming
pool is the main amenity. It is the feature most likely to
grace the cover of your FOR RENT advertisements and
is usually situated prominently at your rental office. Using
automated water chemistry controllers ensures that your
pool & spa water will be clear and inviting when showing
your property to prospective tenants.

More importantly, using automated water chemistry helps
ensure your water is
SAFE. The CDC recommends
testing pH & disinfectant
levels hourly when in heavy use.
Our controller utilizes a digital microprocessor design
which checks and adjusts the water chemistry

After last summers unprecedented outbreak of 1,800
confirmed cases of
Crypto in nearby Utah, we strongly
recommend you automate your pool & spa water
chemistry, Now.
Especially  Spas
Proper water chemistry is notoriously difficult to maintain
in public spas. High temperatures that quickly dissipate
disinfectant, small water volumes, poor hygiene and high
bather loads all conspire against the best intentioned
pool operator. Poor water chemistry also greatly shortens
the life span and voids the warranty of expensive spa

Since installing our first controller on a spa in January of
2007, we have virtually eliminated all those issues on that

Many jurisdictions now require automated water
chemistry controllers on public spas.
It is only a matter of time until Nevada adopts this
requirement. We recommend you don't wait and
automate now.
No More Closed Pools
Westside Pool CAT System Installed on Spa
January 2007
More Info
Controller Concepts: ORP and Oxidation

A well-known study performed by Dr. Jim Brown of the
Oregon State Health Department about fifteen years ago
made it crystal clear that ORP is the qualitative measure of
choice for sanitarians or operators evaluating the safety of
pool variables plus plate count (bacteria density) and,
finally, ORP. Extremes showed up in pH from 5.7 through
8.3, combined chlorine from 1.4 to 34 ppm, free chlorine
from 0 to 30 ppm, cyanuric acid (what’s it doing in a spa??)
from 0 to 1,300 ppm, plate counts from 0 through 15,000,
and even Pseudomonas up to 12,400! The only correlation
that stood up throughout the study was the relationship
between ORP and the presence of pathogens. Virtually no
plate count existed in the spas where ORP values were
found to be above about 630 millivolts, while lower values,
no matter the free chlorine residuals present, all had
dangerous or near-dangerous levels of pathogenic life

Among the unsafe pools in the study, chlorine residuals bore
no resemblance to the plate-count values. Even when the
free chlorine was as high as 4 ppm, a significant plate count
existed because the ORP in that spa was 537 mV. The pH
was 6.9, so why was the ORP so low in that spa’s water?
Excessive cyanuric acid was the culprit, as was the case in
all but two of the thirteen spas exhibiting ORP levels at or
below 630 mV. No matter the reason for low ORP, however ?
low sanitizer, CYA, high pH, chloramines ? you could count
on unsafe water and eventual turbidity.

By Kent Williams ~ kent@ppoa.org
Executive Director and Editor
Professional Pool Operators of America

Conventional Swimming Pool Water
Testing & Treatment Provides
Inadequate Defense

While many swimming pool operators and health officials
believe that a free chlorine residual of 1.5 to 3.0
parts-per-million provides sufficient sanitation, there are
several factors which have a significant impact on the
bactericidal effectiveness of the sanitizer.  For example,
correcting the pH of a swimming pool or spa from 7.8 to
7.4 at a fixed free chlorine residual will cause a dramatic
reduction in the kill time for E. coli.  

Most regulatory agencies set water quality requirements
based on the measurement of free chlorine residules with
DPD test kits.  However, free chlorine is composed of two
distinct parts or species known as Hypochlorous acid
(HOCl) and Hypochlorite ion (OCl-), which are not equal in
their ability to sanitize.  The ionic form of chlorine (OCl-) is
slow acting, while the Hypochlorus acid (HOCl) is 80 to
300 times more effective.  

Unfortunately, bather loading and chemical dosing
constantly influence the dissociation between the two
chlorine species, rendering mandated sanitizer residual
levels and the DPD measurement thereof a weak tool in
maintaining bacteriological efficacy.

CAT Controllers

When it comes to maintaining healthy
pool water, ORP is actually more
important than ppm. What’s more, relying
on ppm readings alone can provide a
false, and dangerous, sense of security.

Decades of research have shown that ORP is a direct
measure of the sanitizer’s oxidation and disinfection strength
in the water. For instance, the polio virus dies in five minutes
at an ORP level of 550 millivolts (mV), but at a 650 mV ORP
level, it takes only 30 seconds to kill this virus. Add another
100 mV and the kill time is approaching one second! Kill
rates have been similarly established for all waterborne
pathogens along the ORP rate-of-disinfection scale — even
for cryptosporidium, E.coli, giardia and legionella

By Jim Tanner, Siemens Water Technologies
May 2006 Jim Tanner is national sales manager of the
Aquatic Division at Stranco/Siemens Water Technologies.
His extensive aquatics background includes consultation and
17 years of designing and constructing aquatics facilities.
© 2006, Aquatics International
Web Based
Monitoring & Data Logging
Westside Pool CAT System
Installed on 50,000 Gallon Pool
January 2008
WSP CAT System
Installed on Spa
March 2008