Archive for the ‘Commercial/municipal pools’ Category
Swimming Performance and Disinfection Byproducts: Biocides, Biofilm and PoolNaturally® Plus
By David Knighton MD
Co-Founder and CEO of Creative Water Solutions and PoolNaturally® Plus
Introduction
Walk into a building with a pool and you can instantly tell it’s there by the smell. No matter how big the building, small the pool, or robust the heating and ventilation system, that characteristic “chlorine” smell is there. If you are like me, a few minutes of exposure to the smell will bring tightness to my chest, itching to my eyes, and after about 20 minutes a light headed feeling. Go outside and it all goes away in about an hour. Swim and it can take days to return to normal. Competitively swim or swim daily and you probably get so used to the air you become acclimated to the irritation of disinfection byproducts (DBP). In the past few years, a lot of research has defined what causes this smell, what effect it has on swimmers, and what can change the creation of DBP’s so the pool becomes a “you don’t know there is a pool until you see it” experience.
How are DBP’s formed?
DBP’s are formed when chlorine, bromine or any halide molecule used to kill bacteria in the water, combines with biologic molecules that contain carbon and nitrogen. The most prevalent molecule in the swimming environment is urea from urine and sweat. Urea undergoes chemical changes in the pool and combines with chlorine or bromine to form over 30 different DBP’s. Some of these molecules stay in the water and others are volatile so they diffuse into the air above the water and eventually into the entire building. The act of swimming actually increases the concentration of DBP’s by churning up the water and increasing the concentration of these molecules in the air.
What Effects do DBP’s have on people?
We know a lot about the effect of one DBP – chloroform – since it was the most commonly used anesthetic for decades. The fancy name for this class of DBP is trihalo-methane (THM). There are many different THM’s with different effects on people, just like there are many different types of DBP’s that have different effects on people. We will look at chloroform and trichloronitrate.
Chloroform inhaled at a concentration of 10,000 ppm puts you to sleep. Prolonged exposure at this very high level will kill your liver, depress your heart function and kill you. In human volunteers, exposure to 4,100 ppm causes serious disorientation and 1,000 ppm causes dizziness, nausea, fatigue and headaches. Prolonged exposure to as little as 10 to 200 ppm can cause liver enlargement and effects on the central nervous system. For a reference, we have measured THM concentrations in commercial indoor pools in the 2 – 3 ppm range.
Application of chloroform to the skin causes redness of the eyes and itching of the skin. One study of people exposed to low levels of chloroform in their drinking water showed a correlation between chloroform concentration and rectal and bladder cancer. In fact, an international health agency classifies chloroform as a carcinogen for humans.
Other studies, especially from Europe, document the effect of trichloronitrate on swimmers. They conclude that this DBP is related to reactive airway disease or asthma in people who swim frequently. Another study shows that DBP’s are associated with changes in DNA in urinary bladder cells that correlate with an increased risk of cancer.
To summarize, DBP’s not only smell bad, they irritate your skin, eyes and lungs; cause central nervous system changes such as dizziness and headaches; cause fatigue; and with prolonged exposure are potential carcinogens.
How do DBP’s affect swimming performance?
Any athletic performance is determined by muscle contraction. Muscle contraction is an energy consuming activity that is related to oxygenation of the blood and blood flow to and from the contracting muscle. Oxygen is used along with blood delivered nutrients to produce energy so the muscle cells can contract and propel the swimmer through the water. Oxygen is delivered to the blood through the lungs as we breathe. Oxygen is then carried by our red blood cells to all tissues in our body including muscles, by blood flow. Blood flow depends on our heart to pump the blood and arteries to carry that blood to our exercising muscles.
At rest, our muscles require very little blood flow and oxygen. As we start to exercise and use our muscles to propel us through the water, they consume all the oxygen and nutrients in the area, then tell their arteries to dilate and send more blood. That causes our hearts to beat faster to supply more blood for the dilated arteries and that eventually causes us to breathe faster to deliver more oxygen to our lungs. A big part of athletic training, is to maximize this energy transport system from air to muscles. The more we exercise, the better the system works. The better the system works, the more we can exercise.
DBP’s affect performance in a number of ways. First, the air just above the water is what a swimmer inhales during swimming. That air has the highest concentration of DBP’s. The amount of oxygen in air follows the rules of physics. The higher the concentration of DBP’s, the fewer oxygen atoms in the same amount of air. So the swimmer in a pool with high DBP’s needs to move more air in and out of their lungs to remove the same amount of oxygen as a swimmer in a pool with lower DBP’s.
DBP’s like trichloronitrate cause lung irritation and narrowing of the tubes that bring air into our lungs. Because of the narrowing, less oxygen gets to the microscopic areas of our lungs where the delivery of oxygen to the blood occurs. Therefore, we need to move more air to extract enough oxygen for our exercising muscles. One result of this lung irritation is the use of drugs, called bronchodilators, that open up the airways and others, that control the inflammation caused by the irritating DBP’s. This asthma is a significant problem in many competitive swimmers.
Like most diseases, some people are more sensitive to DBP’s than others.
Those swimmers who are sensitive to DBP’s have to work harder to provide adequate energy for their contracting muscles than those who are less sensitive to DBP’s irritation.
Performance and conditioning is all about maximizing oxygen extraction from the air, blood flow to the muscles, and removal of waste products from the exercising muscle. DBP’s play a significant role in oxygen concentration in the air; delivery of air to the blood, and pumping of blood to the muscles. Along with the other health effects of chronic exposure to DBP’s and the uncomfortable irritation they cause, swimmers should do everything possible to minimize the concentration of DBP’s in their pools.
What can swimmers do?
Since urea is one source of nitrogen containing bio-molecules that form DBP’s, swimmers can reduce their formation by not urinating in the pool. Sweat is another source of urea that cannot be easily controlled since training causes increased sweating. I’ve talked to many competitive swimmers who tell me they don’t want to stop their training to go to the bathroom to urinate or that their coaches won’t let them take a break. Changing this would help create a more healthful environment for every swimmer, coach, lifeguard, and spectator.
What can facilities can do?
Ventilation
To understand the role of ventilation in this problem, we need to remember that DBP’s are at their highest concentration on the surface of the water. This is the boundary layer where there is little air movement. Traditional ventilation brings outside air inside, warms it up or cools it off depending on the temperature, and then moves it through the building, eventually pushing the air back outside. This is a very expensive process. Moving more air from the outside and through the entire space of the natatorium doesn’t address the area of the pool where DBP’s are in their highest concentration. Increasing the air movement at the surface of the pool does result in a decrease in the concentration of DBP’s. Paddock Evacuator Company’s Chloramine Evacuation System achieves this by a system that moves the air across the boundary layer and moves it outside.
Water treatment
Water disinfection and formation of DBP’s is a classic “rock and a hard place” situation. Chlorine and bromine are very effective and efficient killers of swimming (planktonic) bacteria and algae. They accomplish this through their chemistry. They are very reactive with other atoms and molecules. This reactivity oxidizes proteins and sugars in the cell wall of bacteria and algae, but also reacts with carbon and nitrogen containing compounds to form DBP’s in the water and air. It is the main way we control bacterial growth in most water systems. Even treatment systems, such as salt pools, control bacterial growth with chlorine. You don’t have to add the chemical, a reactor in the pool creates bio-reactive chlorine from the chloride ion in common salt.
When we started treating commercial pool water with PoolNaturally® Plus we found that the air quality in the pool area improved in a couple of days and the air in the entire facility was significantly improved after a week of treatment. Over time our customers starting saying that the only way you know there is a pool in the building is to see the water. Swimmers, coaches, lifeguards, and pool patrons all reported less eye, skin, hair, and lung irritation. After a swim meet in one of our pools, many swimming teams demanded that their facility add PoolNaturally® Plus.
To measure the effect of PoolNaturally® Plus on DBP concentration, we did a study with a fitness club to measure the THM in the air above the pool surface and the water in their two indoor pools (75,000 and 86,000 gallons). We measured levels weekly, for two weeks before PoolNaturally® Plus was introduced and then about every other week for 33 weeks. They have a high bather load and use chlorine for disinfection. We measured a steep decline of THM in the water resulting in 75% reduction in 33 weeks. In the air above the pool the chloroform concentration was decreased by 55%. The air quality improved just like in our other indoor facilities.
How does PoolNaturally® Plus affect DBP production?
The quick answer is we don’t know. We do have a hypothesis. PoolNaturally® Plus is made from Sphagnum moss leaves. In our laboratory, over the past 8 years, we have shown that PoolNaturally® Plus inhibits biofilm formation. Biofilm is a slime like substance that protects bacteria that adhere to the pool or filter surface. In fact, most bacteria prefer to adhere to a surface and cover themselves in biofilm, than to swim unprotected in the water where chlorine can kill them. We think the unique environment inside the biofilm helps convert urea and other organic compounds into DBP’s. We postulate that inhibiting biofilm reduces the production of DBP. The product could also have a direct effect on the DBP produced in the pool. We know the concentration is significantly decreased. We don’t quite yet know how.
PoolNaturally® Plus and swimming performance
We know competitive swimmers like training in water conditioned with PoolNaturally® Plus. We know that swimmers with asthma report that they don’t use their inhalers when they swim in outdoor or indoor pools where water is treated with PoolNaturally® Plus. We also know that lifeguards and aquatic professionals report fewer respiratory problems working around pools with PoolNaturally® Plus. We don’t know if their training and eventual performance is improved, and it will take time and study to know if the reactive airway disease, DNA changes and other health effects of DBP’s are improved.
Summary
- Use of chlorine and bromine as disinfectants in pools produces disinfection byproducts that have significant health and performance effects.
- DBP’s, such as chloroform, other THMs and trihalonitrates irritate people’s eyes, skin, lungs, and central nervous system.
- Pool water conditioned with PoolNaturally® Plus reduces the “chlorine smell” in treated pools and resulted in a 75% decrease in THM in commercial pool water and 55% reduction in natatorium air.
- Patrons of pools treated with PoolNaturally® Plus report significantly less eye, skin and lung irritation.
References
Articles about asthma and chlorine:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1747493/
http://www.pslgroup.com/dg/2076de.htm
http://www.erj.ersjournals.com/cgi/content/abstract/19/5/827
http://swimming.about.com/od/allergyandasthma/a/cl_pool_problem.htm
http://findarticles.com/p/articles/mi_m0CYP/is_13_111/ai_111200649/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626429/
Chloroform and effects on humans:
http://www.osha.gov/SLTC/healthguidelines/chloroform/recognition.html
THMs and bladder and colorectal cancer:
http://www.biomedcentral.com/content/pdf/1477-3163-3-2.pdf
More about Paddock Evacuator Company’s Chloramine Evacuation System:
http://www.paddockevacuator.com/about_evacuator.html
More about Creative Water Solutions’ PoolNaturally® Plus system:
Dramatic New Benefit of Sphagnum Moss Water Treatment Method Discovered
Creative Water Solutions (www.cwsnaturally.com — CWS) announced October 19th, 2011 that it has filed for a patent under the heading —Use of Moss to Reduce Disinfectant By-products in Water Treated with Disinfectants. The patent will cover all of its products that use the moss-based water treatment, including PoolNaturally®, PoolNaturally® Plus, SpaNaturally®, and SpaNaturally® Plus.
After a 33-week scientific study of two large, commercial indoor swimming pools in the Twin Cities area, CWS measured the levels of DBPs and VOCs and the impacts of the resulting from the use of Sphagnum moss. The test found that its sphagnum moss product, PoolNaturally Plus, dramatically reduced DBP and VOC levels, reducing odor, decreasing chemical smells and their unpleasant side effects on swimmers, lifeguards, maintenance and other staff.
DBPs are created in pool systems through the chemical reaction of the chlorine disinfectant with organic matter in a pool, or spa. Many DBPs are toxic compounds, such as trihalomethanes (THM) and halocetic acids, and are the main source of the odor and health issues associate with pool facilities and use.
“Our tests found significant DBP reductions and air quality improvements, clearly establishing another significant benefit of the PoolNaturally-Plus system. THM’s, such as chloroform, are created in the water and then move into the air of a facility. The demonstrated reduction of THM’s in the pool water correlates nicely with the reduction of chloroform in the air and the subsequent increase in air quality” says Vance Fiegel, CWS’s Chief Scientific Officer and co-founder. “Our data shows that besides reducing the amount of chemicals needed to treat water (and lessening irritants to swimmers, maintenance time and corrosion of motors and liners) the moss is also providing measureable air quality benefits:
- THM levels plummeted between 73-80% once the moss was introduced into the pools.
- Chloroform showed a 55% reduction in the air of the pool facility.
According to Dr. David Knighton, MD, CWS President, CEO and co-founder, the scientific data reflects the anecdotal reports the company has consistently been receiving from management and staff at other indoor swimming pools.
“We are very excited to discover yet another benefit of this miracle plant and innovative water conditioning agent,” Knighton notes. “Our customers at many college pools and those at indoor water parks like Chaos, located in Eau Claire, Wi., can corroborate our most recent scientific discoveries about air quality enhancement with the personal evaluations and experiences of those who work daily in an enclosed swimming environment.”
Knighton cited a representative case study recently done at Chaos with Barry Thompson, a retired Navy Master Chief who helped design the facility and currently is its chief operator:
· At most water parks, chlorine disinfection by-products permeate the air at a park’s indoor and outdoor areas: “You can usually smell the heavily chlorinated water in the parking lot. At Chaos you don’t get that smell inside or outside — or on your clothes and in your hair after you leave,” Thompson says.
· Lifeguards are reporting a dramatic reduction in headaches from chloramines and disinfection byproducts due to the reduced usage and the increased efficacy of chlorine to deal with bacteria producing agents and organic material in the water.
· The lifeguards and other staff are reporting less absenteeism thanks to a more natural, less chemical work environment.
For more information — or to interview Vance Fiegel or Dr. Knighton — please contact Martin Keller, Media Savant Communications Co., 612-729-8585, kelmart@aol.com
Creative Water Solutions Involved in Energy Efficient Makeover at Debbie Meyer Swim School
Creative Water Solutions is proud to announce its involvement and support of the Debbie Meyer Swim School Makeover Project.
Check out the exciting makeover at the Debbie Meyer Swim School and all the various energy savings that can be achieved by applying current knowledge and the latest technologies to maintain superior water clarity and sanitation
Creative Water Solutions is Recognized by The Minnesota Pollution Control Agency for Their Work with St. Paul Public Pools
The Minnesota Pollution Control Agency will be awarding Creative Water Solutions for its work with the city of St. Paul and their public pools. With the help of Creative Water Solutions and its Sphagnum moss products, the city of St. Paul dramatically reduced chemical usage at all of their municipal pools. Creative Water Solutions’ Sphagnum moss product has been solely responsible for saving St. Paul over $70,000 by reducing both chemical usage and maintenance/labor hours.
The award will be given at the Minnesota State Fair on August 31, 2011 in the EcoExperience Building.
If you would like to learn more about Creative Water Solutions work with The City of St. Paul and the award, click on the video link.
Local water park the first in the world to use a specific variety of moss to treat their water
A local water park is said to be the only water park in the world using a revolutionary method to condition their water and it’s completely green.
Chaos water park in Eau Claire is using a fraction of the chemicals and chlorine they once used because PoolNaturally. A product made from Sphagnum moss that’s imported from New Zealand but the future of this water treatment system is a bit closer to home.
Click on the link for the full story: First water park in the world to use sphagnum moss to treat water
Summer is on its Way! Water Safety Recommendations
During the summer months, there’s nothing better for adults and kids alike than taking a dip in a nice, cool swimming pool, lake, or river. Summer is also when we head to the lake and rivers with our boats, jet skis, kayaks, etc.
Yet, as we know from recent events, water fun can swiftly become tragedy if some simple, basic safety rules aren’t observed. Make sure you and your family are water safe by following these safety policies:
BASIC WATER SAFETY
Learn to swim
The best thing anyone can do to stay safe in and around the water is to learn to swim. The American Red Cross has swimming courses for people of any age and swimming ability.
Learn CPR and insist that babysitters, grandparents, and others who care for your child know CPR. The American Red Cross and the Minnesota National Safety Council both offer CPR classes.
Never leave a child unobserved around water—any water, including pools, spas, bath tubs, etc. Adult eyes must be on children at all times when around water. The average child stays on the surface of the water for only 10 seconds and the drowning process can start after they are submerged within 20 seconds.
It takes as little as 2 inches of water and 2 minutes for a child to drown. Toilets and buckets of water can be deadly to toddlers, who are top-heavy and can fall over head first. If you have toddlers in your home, always keep the toilet seat down and never leave a bucket of water unattended.
Always swim with a buddy; never swim alone, even in your own pool.
Wear a lifejacket or PFD whenever possible, the Personal Floatation Device must be US Coastguard approved and fit properly.
Don’t swim if you’re under the influence of alcohol or other drugs.
POOL SAFETY
Make sure the depths of your pool are clearly marked. Teach children and other inexperienced or non-swimmers to stay in the shallow end.
Post CPR instructions in the pool area.
If you have a cordless (not cell) phone, keep it with you at the pool. If there is any pool emergency, call 911 IMMEDIATELY; then attempt rescue efforts.
Always keep basic lifesaving equipment by the pool and know how to use it. Pole, rope, and personal flotation devices are recommended.
Enclose the pool completely with a self-locking, self-closing fence with vertical bars. Openings in the fence should be no more than four inches wide. The house should not be included as a part of the barrier.
Pool covers should always be completely removed prior to pool use.
Consider installing an alarm that will sound if anyone or anything falls in the pool. Remember: A child can drown in less than two minutes.
Never leave furniture near the fence that would enable a child to climb over the fence.
Keep toys away from the pool when it is not in use. Toys can attract young children into the pool.
If a child is missing, check the pool first. Go to the edge of the pool and scan the entire pool, bottom, and surface, as well as the surrounding pool area. Keep your pool water sparkling clean so if someone is on the bottom, they can be seen.
Make sure your pool deck is made of or treated with slip-resistant materials.
In public swimming pools, always swim in areas supervised by a lifeguard and read and obey all rules and posted signs.
LAKE & RIVER SAFETY
Children or inexperienced swimmers should ALWAYS wear a US Coast Guard-approved personal floatation device/life jacket when around the water.
Watch out for the dangerous “too’s” – too tired, too cold, too far from safety, too much sun, too much strenuous activity.
Set water safety rules for the whole family based on swimming abilities (for example, inexperienced swimmers should stay in water less than chest deep).
Be knowledgeable of the water environment you are in and its potential hazards, such as deep and shallow areas, currents, depth charges, obstructions and where the entry and exit points are located. The more informed you are, the less likely you are to be injured or killed.
Use a feet-first entry when entering the water.
Living Green Expo at the Fairgrounds
May 7 & 8 Creative Water Solutions and Recreation Aquatic Solutions will be at the Living Green Expo
Living a healthier, safer and more sustainable life can be easy, and it can save you money.
The Living Green Expo (May 7-8 at the State Fairgrounds) is the one place in Minnesota to learn about all the latest in products, services and information to help you live greener. The annual spring tradition is one of the largest and most successful green events of its kind, and it is the largest zero-waste event in the state.
The Living Green Expo offers something for everyone, including showcasing simple ways to protect the family and home from toxins, explore energy efficient and environmentally friendly alternatives, grow and eat better foods and protect our planet for future generations.
New this year, The Expo has an expanded layout, Friends School Plant Sale partnership, the first Green Wedding, an Eco Kids Parade, a Complete Streets in Action demonstration and Electric Vehicle Experience. Free Chinook Books given to the first 200 visitors each day. Secure bike storage is available. Metro Transit provides shuttle services at the Expo and free transportation to and from the Expo with the Go Greener Pass.
No matter where you are on the “green spectrum,” the Expo has something for you.
Swimming Pools and Asthma
During our test this last summer at the St. Paul, MN outdoor aquatic park we surveyed the swimmers twice a week. One of the most striking findings was that swimmers with asthma did not need to use their inhalers when swimming in the pools that were conditioned with PoolNaturally Plus. We then treated the indoor aquatic park in St. Paul and had similar results.
Able to Swim Again
In fact one lady wrote to me about her inability to swim indoors due to her asthma. She was a competitive swimmer in her younger years and had to stop swimming because of severe breathing problems from asthma caused by the air in the pool. She heard about the sphagnum moss treated pools and how people could swim without using their inhalers so she tried swimming again. She reported that she could do a full workout without breathing problems and thanked me for “giving her back her favorite sport”.
With a little research the relationship between recreational and home water, chlorine and asthma became clear.
The Chemical Reactions
Here is what happens when we use chlorine to sanitize water in a pool or in our municipal water supply. As it turns out chlorine is not the problem. A byproduct of chlorine and biological molecules that contain nitrogen is the formation chloramines. These chloramines come in many different forms such as mono, di, and trichloramines. One of these compounds, a molecule called trinitrochlorine, has been implicated in causing airway irritation.
Trinitrochlorine is a volatile molecule that is extremely irritating to tissues such as your eyes, skin and airways. Because the molecule is volatile, it rises to the surface of water and is easily inhaled. In fact, in a pool, the levels of trichloronitrate are highest in the air right on top of the water. So every time a swimmer takes a breath, they inhale an irritant that causes airway constriction called reactive airway disease. The smell we all associate with a chlorine pool is actually the smell of the multiple species of chloamines, not chlorine. The problem is that chlorine is so reactive, it immediately finds and combines with nitrogen containing compounds to create chloramines..
Correlation between Pools and Asthma
A recent study reported in the pediatric literature, showed that children who are repeatedly exposed to swimming pools have a significantly higher incidence of reactive airway disease or asthma, than those who aren’t exposed to pools.
In our research laboratory, we are currently studying why the pools treated with PoolNaturally Plus don’t cause this reactive airway response, skin irritation, or burning eyes and don’t smell. We know that for chlorine to become trichloronitrate you need chlorine, nitrogen containing biological molecules and a low pH. It could be that the amount of biofilm in the pool correlates with the amount of trichloronitrate because biofilm contains and produces huge amounts of nitrogen containing molecules and it creates a local microenvironment that has a very low pH. It could therefore be the “engine” that drives the formation of these toxic molecules. In the laboratory we know that the moss in PoolNaturally Plus inhibits the formation of biofilm and if our hypothesis is correct it could greatly reduce the formation of chlorine to trichloronitrate by removing the primary nitrogen source, the biofilm . We will find out with further research
Aquatics International recognizes CWS’ Knighton in Power 25 Reinventors
Creative Water Solutions President and co-founder David Knighton, MD has been recognized by Aquatics International magazine as one of their Power 25 Reinventors. Successful testing of sphagnum moss-based PoolNaturally Plus at Highland Park Aquatic Center in St. Paul, MN, during the summer of 2009 marked CWS’ entrance into the commercial side of the aquatics industry. Read more at Aquatics International.
Cyanuric Acid and Last Summer’s Journey
This last summer we added our Sphagnum moss pool product to the Highland Park Aquatic Center in St. Paul. We treated two pools. One was a 430,000 gallon Olympic pool and the other was a 22,500 gallon children’s activity pool. You can read about the results on our website.
One lesson we learned involved cyanuric acid, outdoor pools, and chlorine. The accepted dogma is that cyanuric acid is required for outdoor pools and spas to stabilize the chlorine against UV degradation. In fact, most granular or solid chlorine sold in stores is stabilized with cyanuric acid. Dichlor and Trichlor have cyanuric acid in the formula.
When cyanuric acid interferes with chlorine
We started to try and understand the chemistry and science of cyanuric acid because of its side effects. Cyanuric acid above a certain concentration (which is dependent on pH) inhibits chlorine’s (hypochlorous acid to be precise) ability to oxidize bacteria. Failure to oxidize means no killing.
We also found that cyanuric acid is denser than water so it sinks to the bottom of a body of water. Therefore, the level of cyanuric acid on the surface of the pool or spa is the lowest level in the pool and it increases from there to the bottom. It will be the highest in the deepest part of the pool.
We tested this at the Olympic-sized pool. We sampled water at the bottom, middle and top of the pool. The cyanuric acid was set for 40 ppm. At the surface the level was 30-40 ppm, in the middle it was 60-70 ppm and at the bottom it was 100 ppm. From the middle of the pool to the bottom hypochlorous acid was essentially ineffective.
The other fact about cyanuric is that it is nonvolatile. That means as you add more and more to your pool or spa the concentration continues to increase. The only way to decrease the concentration is to empty some water and replace it with fresh water without cyanuric acid so you dilute out the chemical. In places where the spa or pool is full all year long, the concentration of cyanuric acid can increase to the point where the pool has no effective chlorine. I think this is why most pools have algae outbreaks starting in the bottom of the pool. The high cyanuric acid levels inhibit hypochlorous acid so no killing of algae occurs.
The experiment
So, after we learned this, I decided to decrease the cyanuric acid level in the pools gradually to see if it is really needed. The pool engineers told me “if you do that there will be no free chlorine in this pool in the morning.” We agreed to decrease cyanuric acid by 10 ppm each week and monitor the results. The free chlorine levels never decreased and the combined chlorine remained at 0. We decreased the cyanuric acid to zero and never added any more for the rest of the summer. The levels slowly decreased to zero as makeup water diluted out the cyanuric acid. The children’s activity pool behaved exactly the same.
In another pool we treated we were able to manage the large pool all summer without any cyanuric acid and maintained free chlorine levels from 1-3 ppm with no combined chlorine all summer.
Water treated with moss doesn’t need cyanuric acid
The bottom line is that with moss treated water, cyanuric acid is not needed. The mechanism for this probably centers around biofilm. I don’t think that cyanuric acid prevents chlorine from UV degradation or the free chlorine levels would have decreased in the outdoor pools we treated. We know the moss inhibits biofilm formation in the laboratory and know that biofilm absorbs chlorine. We know that free chlorine levels skyrocket when moss is added to the pool and to maintain a level of 1-3 ppm free chlorine, the chlorine added to the pool decreases by over half. So a pool with moss doesn’t need cyanuric acid. That allows the chlorine added to the pool to remain active providing effective microbial control.
