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Back to basics-Water quality and skin irritation by J. Kevin Tucker
Recently, I was speaking with a commercial pool owner. He told me that he had a purple color on the walls of his pool. With just a couple of questions, I could determine the problem. I also suggested a simple way to remove the color from the pool. However, the basis for the problem was a bit different- it’s back to the basics of water chemistry to find a viable long term solution to the problem.
The situation is the same with skin irritation in pools and spas. If you simply want to reduce the skin irritation symptoms, I’m sure that there are a wide variety of lotions and oils readily available for your skin. However, if you want to look into the actual cause, then we need to go back to the basics of water chemistry.
There are many courses available (check with NSPF at www.nspf.org) and hundreds of books. So this will be a short look into the most common causes of skin irritation caused by water quality-and the solutions.
In this simplified view there are probably 4 primary likely causes for skin irritation:1) Chlorine/bromine related.2) pH related.3) Bacterial rashes.4) Overuse.
First, let’s look at Chlorine. Then, we will look at other water quality factors that may also contribute to skin irritation.
Often I hear people describe that they have a rash. They have been to the doctor and the doctor has told them that they are allergic to chlorine. Although I am sure that this condition does exist, it does not make sense in about 99% of the cases- -maybe 99.9%. If this person that has concluded that they are allergic to chlorine, then how are they able to take a shower or wash their hands or, heaven forbid, drink water with chlorine?
Chemically, the active chlorine in swimming pool water is the same chemical as the chlorine in drinking water. Depending on the pool, the community and other factors, I have seen many cases where there is less total chlorine in a commercial pool than there is in the municipal water system. Wait! I do understand that the opposite is very, very true. There are many well maintained municipal water systems compared to poorly maintained swimming pools where the opposite is true as well.
So, what is important here? The first step to determining the source of the rash is to determine the quality of the swimming pool and spa water. The recommended ranges may vary a little from one area or state to another, but generally, the recommended Free Available Chlorine level should be about 1-5ppm. Many pools operate very effectively at levels around 1 ppm. There are many factors to be considered to determine the optimal range for a specific application.
Most importantly, I suggested a Free Available Chlorine (FAC) level of…(???)
What is Free Available Chlorine?
When you dissolve any source of chlorine in clean (lets go to the extreme-distilled/purified) water, you get Free Available Chlorine. Free Available Chlorine is what kills bacteria, viruses, algae, etc. FAC is very effective for killing and oxidizing many organics in the water. Unfortunately, when the first munchkins jump into the water, sweat, body oils and other organics combine with that good Free Available Chlorine and create Combined Chlorine or Chloramines.
The problem with Choramines is that they don’t kill nearly as quickly and effectively and they cause irritation. As little as .2 ppm of Chloramines can cause eye and sinus irritation! So, when I go swim without my goggles and my eyes are irritated as soon as I swim a length of the pool- – most of the time the problem is Chloramines in the water. Unfortunately, the average person says” too much chlorine!” But the reality is that there actually may be not enough Free Available Chlorine to keep the pool sanitary-although the pool smells like “chlorine”
It is also true that several other things can cause that eye irritation–but generally when the irritation is that immediate, it is most likely a high level of Chloramines.
You could have irritation from excessive chlorine– including Free Chlorine levels– but generally those levels would be as high as 10ppm or more. Most people will not notice a problem in 10ppm – as long as the other water quality factors are within the proper range.
Free Available Chlorine plus Combined Chlorine equals Total Chlorine. You must be able to test for 2 of the 3 factors in order to properly maintain the pool or spa. Most health departments require testing with a DPD test kit. You may have an automated system that measures the sanitizer effectiveness with electronic probes, but even then the system should be checked for accuracy with a DPD test kit. The DPD test kits turns the test water shades of a pink or purple to determine the amount of chlorine in the water. Each kit is a little different, but generally you use one test solution to test for Free Available Chlorine and another test solution to find either the Chloramine or the Total Chlorine level. Remember – Free plus Chloramines equals Total.
So, the Free and the Total readings should be the same. If they are not the same, then you have Chloramines- bad choramines!
However, one other related issue is testing of the chlorine level if you suspect an extremely high chlorine level. In this situation, the DPD test will bleach out giving you a zero or low reading when the chlorine level goes over about 12 ppm.
If you suspect that problem, 1) dilute the test water with distilled water and retest or 2) use an OTO test kit. This test kit is not generally approved for commercial applications because it does not give you a free chlorine reading–only a total chlorine reading. However, OTO will not bleach out– it turns darker yellow then brownish red, etc, If you get a bright yellow or brown reading with OTO, then your chlorine level is well beyond 10ppm.
Ok, so what do we do about this? First, you have to test the water properly. If there are zero chloramines (remember, just .2 ppm will cause eye & sinus irritation- and could cause skin irritation in the right situation) then we go to the next concern- -pH. If there are choramines present, then we need to get rid of them!
How do we get rid of chloramines?Although you will need to finish testing the water for other factors, we will discuss those factors in another article. It is impossible to treat the water properly, if we don’t know all of the factors- as the different water quality factors affect each other.Assuming that the water is properly balanced-except for those pesky chloramines, then we need to oxidize the chloramines. There are many ways to do this. Many commercial pools today will have an ozone generator or a medium pressure UV unit that will reduce chloramine levels if it is working properly.If not, then we go back to the old standard– we shock the pool.This is part of the confusion for many people. If you smell lots of chlorine in the pool area (because there are lots of smelly chloramines), then why in the world would you want to add MORE chlorine? The problem is the oxidation of the chloramines. If you add the correct amount of chlorine to the pool, within hours, the smell will actually be less because you have oxidized those nasty chloramines.
The rule of thumb is that for every 1 ppm of chloramines in 10,000 gallons of water, you add 10ppm of free chlorine. It depends what type of chlorine you are using to determine the dose. But for example, for a 10,000 gallon pool with 1 ppm of chloramines, I would add 1 pound of Calcium hypochlorite or 1 gallon of swimming pool bleach (sodium hypochlorite).
Obviously, this raises the chlorine level temporarily, so you generally do NOT do this while there are swimmers in the water. The best time is in the evening, after the pool is closed.
Alternatives (Ozone & UV) were listed above, plus there are non chlorine shock treatments that do not raise the chlorine level, but they will oxidize the chloramines and allow swimmers to re-enter the pool after 15 minutes. However, these treatments are a bit more expensive, and if you are using an automated sensor system (ORP), they will throw off the accuracy of the ORP reading for a while. They will also give a false high DPD total chlorine reading for several hours.
Ok, so we have reviewed much of the basics about proper chlorination for your swimming pool and how to avoid skin irritation due to improper chlorination.
I know it’s illogical, but let’s jump to #4, Overuse, in order to gain a bit of perspective. Although eye irritation that you notice immediately is most often due to chloramines, if your kids come home with red eyes after spending the day at the pool– it is quite possible that the water is well balanced. If you stand with your eyes open under the shower for a couple of hours, your eyes are going to hurt, also. But it’s an overuse issue- you are washing all of the natural moisture away from the eye, causing irritation regardless of the water quality. So, in order to diagnose the problem, we need more information than just that someone has red eyes or skin irritation.
Whew– that is probably more water chemistry than most of us want to digest in one sitting- -so we will address the other factors
About the author. J Kevin Tucker
I have been working in and around swimming pools for almost all of the past 40 years.
Like many people in the industry, I started lifeguarding, coaching and teaching swimming lessons. I ran, operated, maintained and programmed pools – mostly large heavily used pools- for over 15 years. For the last commercial pool that I ran, I grew the programs from summer enrollment of about 200 to a summer enrollment of about 1900 in 5 years. I was certified and taught everything from infants to scuba. I trained hundreds of instructors. I have taught aquatic exercise classes (in the late 70s and early 80s) and have conducted aquatics classes for people with disabilities.
After leaving that part of the swimming pool industry, I worked for a swimming pool retailer selling, building, installing and servicing inground pools, aboveground pools and portable spas.
I worked for BioLab, one of the largest swimming pool chemical manufacturers, for 10 years providing sales, troubleshooting and training for distributors, dealers and consumers in the US west of Ohio for residential and commercial applications.
I worked for Sta-Rite for 3 years. At the time, Sta-Rite was a top quality swimming pool equipment manufacturer with the undisputed best training programs available in the industry. I was responsible for sales, troubleshooting and extensive training for proper selection, installation and troubleshooting of swimming pool pumps, filters, heaters, etc.
Since leaving Sta-Rite, I have continued to teach seminars and aid troubleshooting for people in the swimming pool industry. I have also served on the Board of Directors for APEC-Aquatic Professionals Education Council. APEC is a nonprofit organization formed in 2005 for educating and supporting good legislation for the pool and spa industry and the consumer of Texas. I continue to testify and work with the lobbyists to try to provide information that will lead to the best legislation and regulations for the pool and spa industry and the consumers of Texas.
In 2006, I was introduced to the H2OGym product line of aquatic exercise equipment by a friend that had worked for a competing chemical company when I worked for BioLab. I now import from Taiwan and market the underwater treadmills, steppers and other equipment for sale primarily in the US. My company is H2OGym-US, LLC.