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Commercial Pool Problems

Dealing with different pool  standards and requirements.
The Pool and Spa Informational Website

Commercial Pool Questions and Problems.


Scroll down to browse through some archived SWIMMING POOL questions and answers.  Please click the Pool Topics Link, on top of every page, to access a complete listing of Pool Problem subjects, an alphabetized Website Table of Contents, Pool Equipment Information, About Alan Biographic Material and a Pool Glossary. Use the other links to access additional subject information. More information about some new and unique products, for pools and spas, can be found by visiting The Website Store. You'll never know what you'll find and that's always fun. Be better prepared and avoid costly problems!

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How to manage a commercial swimming pool? Commercial Pools cannot always use the same chemicals that are used in typical residential pools, because of the regulations of local health departments. What is permitted will vary from state to state. High bather usage can require specialized equipment and sanitizing practices. Make sure that your pool is in compliance with the latest anti-entrapment requirements. If problems arise, refer to the Pool Problems Page, as a source of problem-solving information, broken down into various categories.  Scroll down the page and click on the linked keywords, catch phrases or images, in the archived answers below, to access additional information, on that topic or product.

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▼     Helpful, Problem-Solving Information, in a question and answer format.     ▼

Commercial Pool Chlorination?

I recently started taking care of a commercial pool and am having problems getting the chlorine levels up. It seems that no matter how many times I clean/replace the filters, add trichlor sticks or shock with lithium, I can't get the chlorine level any higher than 1 on my 4-way test strips. Any suggestions. Thanks in Advance.

Rick S., Bolton Valley, VT, 4/23/2016

There are basically two possibilities here. The chlorine requirements could be so high that the chlorine sticks cannot keep up with the demand. Unless the chlorine feeder is oversized and full, it may not be able to dissolve the product at a fast enough
New!!!  One_Dip Insta_test Strips for pools and spas rate and that explains the need for the shock treatment. Trichlor is not the best way to sanitize a commercial pool. The other possibility is that the test strips are not reading properly. This can happen, if the strips are removed with wet fingers or not stored properly. I suggest that you use something else to verify the results. In either case, you must use products and testers that are allowed for use in commercial pools. State laws vary, on these matters. LaMotte Insta-Test strips are approved for use in some commercial pools. Has anyone ever thought about upgrading the sanitizing? A salt chlorine generator would be an excellent choice, as it is a benefit to both the operator and the pool users. Another thing to consider is the use of ultraviolet sanitizing. It won't replace the chlorine, but will greatly reduce the amount of chlorine required, dramatically reduce the chloramine odor and simplify the water chemistry. I hope that this information will prove helpful.

Sincerely. Alan Schuster, 4/23/2016

Controlling The Water Chemistry?

We run a small community pool and would like to research a better means of adding chemicals. The pool uses liquid chlorine and acid and these are added with feeding pumps, tied into the operation of the filter and pump. The problem is that the bather use is anything but consistent and sometimes there is too much chlorine and other times there is not enough. Are there controllers that can be added? How expensive are they? Thanks for the help.

B. M., Knoxville, TN, 6/23/2014

Yes, controllers can be added that will help regulate the addition of the chlorine and acid. It should give you more u
niform conditions. SoAutoPilot salt chlorine Generators. far as the cost of these controllers is concerned, I will have to pass. There are several manufacturers of such equipment. I suggest that you consult with a pool company that deals with non-residential pools. There are other chemical saving and highly controllable sanitizing methods, that are suitable for use in commercial-type pools. Ozonation, for example, would deal with the introduction of bather wastes and would decrease the amount of chlorine required to maintain a satisfactory level. AutoPilot Salt chlorine generators and UV Sterilizers are other possibilities. Browse through the pages on these topics for more information. Sorry, that I couldn't provide all of the details.

Sincerely. Alan Schuster, 6/24/2014

Reducing The Chlorine Odor?

I operate a commercial indoor pool that gets a lot of use. The odor is a real problem with some of the users. I know that chloramines are the cause, but I can't keep on adding shock, as the pool is very high volume. I have heard the ultraviolet can make a difference. Is there any truth to that? Thanks for the time spent.

Frank B., 5/18/2013

In indoor high-use commercial pools, odor can be an unpleasant feature. You will find the environment of the pool to be vastly improved, within 1-3 days, after installing an Ultraviolet Sanitizer System. The UV rays not only sanitize the water, but dramatically reduce or eliminate the chloramines. When chlorine combines with nitrogen-ammonia compounds, chloramines are formed and produce the chlorine smell that is so obnoxious, irritating and unhealthy. Less chlorine will be required to maintain the customary levels and the overall water chemistry will be less subject to fluctuation and buildup problems. I hope that I have explained some of the benefits.

Sincerely. Alan Schuster, 5/18/2013

Chloramines And Ionization?

A public pool, that I swim at has had chronic chloramine build up that has resulted in air quality issues. The pool is approximately 125,000 gallons with a high bather load and uses liquid chlorine and muriatic acid.  I know there are a lot of factors that go into reducing chloramines, but my question is specific to a copper/silver ionizer.  This equipment was installed at this pool for the sole purpose of reducing chloramines, but there has been no real improvement. According to the owner, it is working, but you wouldn’t know it. Chloramines are consistently above 1 ppm and the air is heavy with the odor. They also state that they shock the pool with liquid chlorine to reach breakpoint. They do not use MPS for shock treatment. My question is whether or not the ionization system, they have in place, is actually capable of breaking down chloramines? My understanding of copper/silver is that they are sanitizers via ionization, but not strong oxidizers. Can you tell me if there are merits to this system with respect to chloramine reduction? Thanks for any insight. You provide a great service.

Richard W.,1/26/2008

You seem to have an excellent understanding of the issues. Ionization alone will not eliminate or reduce the chloramine concentration. It shouldAutoPilot salt chlorine Generators. reduce the amount of chlorine required to maintain a proper free chlorine level, but will have no effect on chloramines. To destroy or reduce the chloramine content, oxidation is required. It can be in the form of chlorine or potassium monopersulfate. Ozone Generators will reduce chloramines and odors very effectively, but will still need some chlorine to act as a backup sanitizer. A salt chlorine generator would have been a better choice, as it manufactures chlorine, right in the pool. The water would be stripped of chloramines, as water passes through the salt cell. State law might enter into which equipment is best suited for a public or commercial pool and this should be considered. I think a better choice could have been made. I hope that this information will prove helpful.

Sincerely. Alan Schuster, 1/26/2008

Unhappy With Biguanide In A Spa?

I manage a large commercial spa. It is indoors, contains 1800 gallons and is heated to 103'. The bather load is about 80 people per day. The filter runs about 10 hours a day on high speed. Currently I am using a Biguanide system. I am very unhappy due to the complexities involved and because I am having problems maintaining water clarity. Chlorine is not an option because of the odor and irritation. From the information I gleaned from your web-site, I am considering converting to Bromine with UV sanitizer and ozonator. As far as the bromine is concerned, do I go with the tablets or 2-part system? What do I use for shock? How do I size the proper ozonator and UV? Thanks for a great web-site. Sincerely.

A. H., New York, 10/5/2008

I am shocked that the NY health department allowed you to maintain a commercial spa , in that manner. Whoever talked you into biguanide was only concerned about their profit margin. You need to treat this, as if it were a pool, as that is what the bather load
demands. The ozone generator, Ultra-Violet Sanitizer and bromine feeder, should be sized to treat a pool. Your three fold approach is sound and is what I would recommend.  I would use an inline bromine feeder and try to keep the level at 3-5 PPM. The ozonator will make it easier to do and allow you to use less bromine, to maintain any given level. The UV Sanitizer makes perfect sense, as it kills virtually all microorganisms, includes the worst offenders.   If you add some sodium bromide to the water, you can use chlorine to shock the spa, as the chlorine will convert to bromine. If reduced chemical usage is the intent, UV sanitizing is the place to start! UV treatment will reduce the microbial populations in the return flow to near zero, without the use of chemicals. However, it cannot oxidize wastes or totally eliminate the microbial population in pool or spa water or prevent the growth of biofilm on the underwater surfaces. Products such ozone or bromine must be used, in conjunction with UV. How much will be required will depend upon actual bather usage. More usage will require more chemicals. In order to assure that adequate oxidation and sanitation exist at all times, I suggest that you try and maintain a level of bromine, at about the normal level or 3-5 PPM. The UV unit will help decrease microbial populations and reduce the amount of bromine, necessary to maintain any given PPM level, by up to 70%. Over time, charting the amount of chemicals added, the bather usage and the bromine level will provide the best indication of actual chemical requirements.  I hope that this information will be helpful.

Sincerely. Alan Schuster, 10/6/2008

Clouded Up?

I am on the board of a homeowners pool and a recent grad of a CPO course however, I need some help on a problem. Our pool is 80,000 gallons. The pH reading is 7.2, FAC is 2 ppm, TA is 220. We use Calcium Hypochlorite as our sanitizer. Our pool opened today and the water was crystal clear. The ambient temperature was 91 °F. Not sure of water temperature. Four hours into our first day the water started to become cloudy. Two hours later very cloudy. We backwashed the filters. Additionally, according to my CPO book we should try the acid column to convert the C03 to C02. I have read several of your answers regarding TA. I am more concerned with the cloudiness. Any help?

Doug, 5/18/2010

 AutoPilot salt chlorine Generators.
It would have been nice to know what the calcium hardness reading was? The use of calcium hypochlorite will raise the calcium level, the pH and the TA. Your TA is already too high and it is likely that the calcium reading is in the hundreds of PPM. That can account for the cloudy pool water problem. Depending on the makeup of the dissolved mineral, lowering the TA might prove difficult, but it should be tried. I suggest that you consider using something other than calcium hypochlorite. Liquid chlorine would seem logical. Even better would be a salt chlorine generator. Otherwise, the increasing calcium hardness levels will only cause more and more pool water clarity problems. Adding mineral treatments will help to an extent, but is not a long term solution. I hope that I have been of assistance. Good luck.

Sincerely. Alan Schuster, 5/19/2010

ORP Confusion?

Having a bit of a bizarre issue with the pool which I run! The Alkalinity is always a bit low (65-75ppm) so have been adding sodium bicarbonate to the pool to bring it up a bit, I use sodium hypochlorite as the disinfectant. The levels of disinfectant are measured in redox only (this is the only one I've ever come across that does not have the PPM reading on as well) which only measures the disinfectant activity and not quantity. Every time, I add sodium bicarbonate the chlorine goes up. does adding bicarbonate interfere with the redox reading, thus causing it to dose more chlorine? Or is it just a freaky coincidence? I really hope you can help as most people run at the mention of redox controllers. Not sure buying a new controller is an option? Yours in anticipation.

Julie, United Kingdom, 8/15/200

It is not a matter of interference. The controller is measuring the Oxidation-Reduction Potential (ORP). As expected,
ORP Testers. adding chlorine causes the reading to rise. The ORP is based on the hypochlorous acid concentration, which rises as the PPM of free chlorine increases. This same reading falls as the pH rises and rises as the pH drops, due to the equilibrium between the hypochlorous acid and hypochlorous ion concentrations. In your case, adding sodium bicarbonate causes the pH to nudge upward, lowering the ORP and causing the controller to add more chlorine to raise the ORP. In order to maintain proper pH and chlorine conditions, the pH and ORP must both be under control. So long as the pH is within the desired 7.2-7.6 range, the controller will keep the chlorine at the proper level. I hope that this information proves helpful.

Sincerely. Alan Schuster, 8/15/2005

Stabilizer and Indoor Salt Chlorinator?

We have two pools/spas with chlorine generators. I read where a stabilizer is recommended, but these are indoor (hotel) pools, so why would I need the cyanuric acid? Thanks for your time!

Steve, Iron River, MI, 3/37/2007

I don't know where you read that. I see no reason that Cyanuric Acid should be required. UV is an outdoor problem. Dichlor is used, indoors, because it is quick dissolving and essentially pH neutral. My guess is that the instructions were not written with an indoor pool in mind. I hope that this information is helpful.

Sincerely. Alan Schuster, 3/27/2007

Calculating Bather Loads?

I have a large group coming into our municipal pool. How can I be sure that the pool will accommodate that number of people?

M. C., 9/8/2005

According to CPO information, the following calculations are used.

Commercial Pools: Surface Area in Square Feet divided by 24 = maximum bathers.
Commercial Spas: Surface Area in Square Feet divided by 10 = maximum bathers.
Please verify that this information is current or applicable to for your area.

Sincerely. Alan Schuster, 9/9/2005

Commercial Salt Chlorine Generators?

We operate a resort with 5 pools, ranging from about 50,000 to 300,000 gallons. All are commercial hotel/resort pools that get a lot of use. Most of the chlorine generators, I've see have limits of 25,000 gallons. Would it feasible to put more than one on a pool in series or parallel? Would that work? Or is it not a good idea on a commercial pool?

Mike R., 2/11/2008

Many salt chlorine generators are designed and sized for residential pools. Others are specifically designed for the AutoPilot salt chlorine Generators.commercial, resort or municipal segment, of the market.  Multiple units can be used to accommodate larger pools. With a salt chlorine generator, over-sizing is better. It provides a reserve capacity that helps pools cope with periods of peak usage. The proper sizing of a salt chlorine generator, for commercial use, is dependent on the following factors: pool volume, maximum bather load throughout the entire day, circulation pump run hours per day, indoor or outdoor location, inclusion of special water features, water falls, fountain heads, negative edge, wave making, slides, etc and what is the maximum water temperature the pool can reach, at the hottest part of the summer.  My recommendation would be AutoPilot, for two reasons. They have a complete line of units, to accommodate pools of all sizes and situations just like yours. In addition, they thoroughly know the topic of salt chlorine generators and have the expertise that you require. When I have a question, I ask them. I hope that this will help with the decision-making.

Sincerely. Alan Schuster, 2/11/2008

Combined Chlorine Issues?

This is not your standard question regarding chloramine reduction. As a Health Inspector I deal with this issue a lot but here I want to ask about speed. Specifically the speed at which breakpoint can be achieved. A health club that closes at 10:00 pm and opens at 5:00 AM tries to beat the clock in super chlorination. With chloramines that reach 1-2 ppm, how fast can breakpoint be achieved with conventional shocking with liquid chlorine? 125,000 gallon lap pool. The CDC discusses contact time in cases of liquid stool contamination. Double the dose of chlorine results in half the time needed for contact. Can this same principle be used in chloramine elimination? 1.0 ppm CC conventionally requires 10 ppm chlorine to reach breakpoint (actually 7.5 or so but who's counting). What about 1.0 ppm CC hit with 20 ppm chlorine? Potassium peroxymonosulfate could be an option, but they do not have a test kit to deal with the interference on testing chlorine. Seemingly pointless, if you don't know you have reached breakpoint. Alan, please hurry! Thanks!

Tim R., 2/16/2008

All chemical reactions, and destroying combined chlorine is a chemical reaction, are partially governed by concentration. This is really a physical chemistry problem, but simply stated, time, temperature and circulation have to be considered, as well. Raising the concentration, will cut the reaction time, but even that is effected by variables. A pool is full is organics, that given time, will form more combined chlorine. If there is 1 PPM of combined chlorine at pool closing time, adding 10 PPM of free chlorine might not be enough, because of the organics present reacting with the free chlorine or the formation of more combined chlorine, from the nitrogenous wastes. Adding 10 PPM of free chlorine could still leave you with more than 1 PPM of combined chlorine. No two pools or situations are the same, so a set figure might not always work. If 10-1 does not produce a combined chlorine of less than 1 PPM, while leaving a free chlorine level, within your state's guidelines, I can see the utility of adding 12-1 or 15-1 or more.  Potassium monopersulfate would be an alternative worth looking into. It might be used, in conjunction, with the regular dosing of liquid chlorine. LaMotte Company offers MPS test strips. I am not sure what your state allows, in terms of alternative sanitizing, but salt chlorine generators, ozone generators or UV Sterilizers can go a long way towards improving swimming conditions and compliance with the sanitation requirements. I hope that I have been of some help.

Sincerely. Alan Schuster, 2/16/2008

Appearance Of Stains?

I operate a 240,000 gallon painted plaster outdoor pool; after using bromine for about 20 years we switched to calcium hypochlorite in 2004. We never had any "staining: problem using bromine, just a minor green algae problem which we handled with the appropriate algaecide.  The summer of 2004  we experienced tan /light brown/yellowish "staining" - on the walls and floor of the pool, starting in the diving well, slowly moving out into the shallower parts of the pool, gradually increasing in quantity as the summer went on. The pool company I dealt with said it was a metal stain and had me use metal treatment products to take care of. Pool was shut down for several days, chemicals added - all pertinent directions followed, pool thoroughly brushed, backwashed sand filters thoroughly and put pool back into operation, using a metal treatment product on a maintenance basis. However, the stains began to return. They can be brushed off if done early in their appearance - but difficult considering the size of the pool.  When you brush it off water in area turns milky. When I opened pool in 2005 since metal staining did not seem to be the culprit we switched gears to algae "staining." I treated pool with shock and algaecide, initially and on a maintenance basis. But the stains appeared same as in 2004. Only thorough brushing kept them somewhat under control for the summer. My question is this? How do I determine for sure what is causing the "stain" to form, and then what to do to prevent or control it. The only thing we changed was switching from bromine to cal-hypo. Each spring the pool is emptied, then cleaned with TSP and an acid wash before refilling and putting into operation. We stay on top of everything else - free and combined chlorine, pH, alkalinity, calcium hardness, filter cleaning, etc. We checked the source water for the pool and nothing changed there.  The pool company I work with is at a loss. Any ideas? Would appreciate it.

Dick W., 3/8/2006

I am not sure that is the answer, but it does fit the facts. Bromine is acidic and will tend to keep the pH and TA towards the lower end, unless adjustments are made. It does not contribute to the calcium hardness. Minerals and metals tend to be more soluble at lower pH ranges. Cal hypo has a high pH and will raise the pH and TA, as product s being added. This tends to decrease the solubility of minerals and metals, as the pH and TA rise. Adding more and more calcium hardness over time only makes for more problems. I suggest that you monitor the calcium hardness and add regular doses of scale treatment. When the calcium level exceeds 400 PPM, scaling becomes more likely, as does metal staining. Calcium hypo may not be the best product to use, in this pool. I realize that there are cost considerations, but liquid chlorine would avoid the increasing hardness levels. Have you ever considered a salt chlorine generator? It will give you more control and less handling and storage problems. And the water will smell and feel better. Good luck and I hope that I have been helpful.

Sincerely. Alan Schuster, 3/8/2006

A Big Pool To Clean?

We will be operation of a large pool, as shown, in the attached photo. Kindly advise best cleaning solutions that can save money and do the Job. This pool will be taking a large quantity of Chlorine to avoid algae. Many thanks for you. Kind Regards.

Rami O. 1/13/2008

Blue Diamond Robotic Pool Cleaner RC
Robotic pool cleaners are very easy to use, effective and do not require any plumbing or installation. They don't just
throw the dirt up for the filter to catch - it actually removes even the finest sediment and debris. They act as a moving main drain and as a second micro-filter. It can clean the pool floor, walls and even the steps. There is not much that you need to do, other than a simple, occasional cleaning.  There are Robotic Pool Cleaners, that are designed for larger commercial pools and have the longer cords and bigger sweeping areas. I hope that this information help get a cleaner pool.

Sincerely. Alan Schuster, 1/14/2008

Cracked Pool Wall?

We operate a 100,000 gallon commercial pool and recently had a crack develop in a wall. It was repaired and painted over. It now seems to have reopened and is probably responsible for a significant water loss. Do you have any suggestions for making a better repair? Thanks for any help you can offer.
Torque-Lock Concrete Crack Repair System.
Martin M., Georgia, 4/21/2009

Most likely this is a stress crack and needs to be stabilized. Products, such as epoxy, can be used, but don't always wor
k while the crack is under pressure to expand.  The Torque-Lock system is designed to make structural concrete crack repair, that are rock solid.  If you want to make the proper repair, this is what you want to use.  Good luck and I hope that this solves the problem.

Sincerely. Alan Schuster, 4/21/2009

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