Category Archives: Water Treatment

FILTRATION: High Rate Sand Vs. Regenerative Media

Until the past 5-10 years, pressure high rate sand filtration was installed on the majority of commercia2468-BethelAquaticCent-90l pool applications.  There were and continue to be other types of filtration such as vacuum sand filters, cartridge filters, diatomaceous earth filters, and others.  But often whether it was due to the type of pool, cost, material handling, operations, or other reasons, high rate sand filters were generally the preferred choice.

But in the last 5-10 years, regenerative media filters have gained a significant portion of the market share, especially with the number of projects pursuing LEED certification.  Instead of diatomaceous earth (DE), which creates material handling challenges for operators, the regenerative media filters use perlite.  Perlite is a volcanic ash material and the overwhelming majority of local jurisdictions allow it to be disposed directly to the sewer, unlike DE.

When comparing regenerative media filtration to high rate sand filtration, there are really two main points of consideration.  The first is the first-dollar capital costs.  It’s not uncommon to find a regenerative media filtration system to be double the cost of a traditional high rate sand system.  Depending upon the type, size and quantity of pools this cost differential may be tens of thousands to hundreds of thousands of dollars.  To offset the capital cost increase most commonly seen when using regenerative media filters, the ongoing operational cost should be less than that of a high rate sand.  A majority of this operation savings is from the reduction in water usage, translating into a reduction in pool chemicals.  When including the potential capital cost savings from a reduction in pool mechanical room space (high rate sand filters traditionally result in more floor space as compared to regenerative media), the payback period analysis can be as little as 3 to 5 years.  However, this payback analysis assumes an indoor pool with operations 365 days per year.  When looking at the payback analysis for seasonal outdoor pools, the time period for the reduction in ongoing operational expenses to exceed that of the capital investment can increase to 20 years or greater.

The second consideration when comparing regenerative media filtration to high rate sand filtration is daily operations and routine maintenance.  The extent of high rate sand filter maintenance typical includes semi-weekly or weekly backwashing (frequency depends on bather loads), replacing the sand media every 10 years or so, and servicing laterals inside the filter tanks as needed (this isn’t an issue for many well-constructed commercial filter tanks).  Regenerative media filters require daily “bumping” of the filters.  This process is automated and it takes approximately 5-10 minutes to shake the media off of the filter elements and recoat.  Backwashing is much less frequent than with high rate sand filters and a significantly smaller volume of water is sent to waste.  Every 4-8 weeks approximately, two filter volumes of water will need to be dumped and new media will need to be introduced to the filter system.  Finally, on an annual basis, routine maintenance is suggested which includes inspecting and cleaning (if necessary) the filter elements and checking torques.

For a quick comparison analysis let’s consider an indoor 8-lane 25 Meter Pool.  The below chart indicates the filter payback analysis for hi-rate sane versus regenerative media filtration.


As you can see the comprehensive capital cost increase for use of the regenerative media filter system is nearly $32,000.  However, the yearly operational increase is approximately $5,000.  Therefore, it will take nearly 77 months for savings in operational expenses of the regenerative media system to payback the initial increase in capital cost investment.  As previously mentioned, as the pool type, size and location (indoor versus outdoor) changes, so too will the payback analysis.

While there are many other factors to consider when comparing high rate sand filtration to regenerative media, the capital cost analysis and daily operations and maintenance are often viewed as the primary considerations for a comparative analysis.  Additional considerations such as filter media, filtration quality and disposal of media should not be overlooked.

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Chemical Treatment Options For Commercial Pools

All public swimming pools require sanitizing systems to eliminate microbes in the water to provide a healthy swimming environment.  There are many options available today and there are some common misconceptions regarding what systems are available and their relative merits.  The purpose of this overview is to provide some basic information about these systems and their effectiveness, safety, and practical application.

There are three basic categories of water treatment systems commonly used in swimming pools: Sanitizers, Supplemental Sanitizers, and pH Buffers.


All public swimming pools must have a chemical sanitizer, as mandated by the local public health code. The function of the sanitizer is to kill micro-organisms.  This is generally done by adding a chemical sanitizer to the water as it passes through the treatment system in the pool equipment room.  This effectively treats the water at the point of injection, but also leaves residual sanitizer in the pool water itself to handle contamination sources in the pool.  The following options are available:imagesCAH3FQ1H

  1. Sodium Hypochlorite
    1. 12% free available chlorine
    2. Liquid
    3. Dilutes over time
    4. Classified as an irritant
  2. Calcium Hypochlorite
    1. 65% free available chlorine
    2. Tablet
    3. Longer shelf life than sodium hypochlorite
    4. Classified as a Class 3 oxidizer and is corrosive
  3. Gas Chlorine
    1. 100% free available chlorine
    2. Gas
    3. Chlorine gas is extremely corrosive and has been known to corrode all metal within an equipment room.
    4. Not allowed by most health codes due to hazardous nature.
  4. Bromine
    1. Commonly used on smaller bodies of water (hot tubs) with low bather loads.
    2. Twice the bromine is required to reach the same oxidation potential of chlorine.
    3. Bromine is a much less aggressive oxidizer compared to chlorine.
    4. Bromine BCDMH is classified as a corrosive – either class one or class two oxidizer. It is not flammable in and of itself, but it may ignite combustible materials in which it comes into contact, and as such is identified as a hazard.
  5. Chlorine Generation (Salt System)
    1. Non-ionized, coarse, sun-dried or pelletized salt (normally in 40 lb. bags) is initially added to the pool water to develop a concentration of 0.5% (5,000 ppm).
    2. A small amount of electricity is used by the chlorine generator during the electrolytic process.
    3. Salt systems generate pure sodium hypochlorite at a near neutral pH and therefore have less effect on pH than most other pool chlorines.
    4. 4 ppm of free chlorine is reported to be ten times more corrosive than 4,000 ppm in salinity.


A common misconception is that salt systems provide a chlorine-free pool.  This is incorrect.  Chlorine serves as the primary chemical sanitizer in all of the above systems except Bromine.


In addition to the above chemical sanitizers, secondary water treatment systems are available to further improve the water quality.  It should be noted that none of these systems are permitted by health codes to serve as a primary source of water treatment.  They are only permitted as supplementary systems.  This is because they do not result in providing any residual chlorine in the pool itself, where contamination is most likely to occur.  Water is only treated in the equipment room.

However, the advantage of these supplemental systems is in their effectiveness at reducing Chloramines (combined chlorine).  Chloramines  are compounds formed when chlorine combines with other chemicals from human perspiration, body oils, and other byproducts.  These chloramines have been shown to affect the air quality in the natatorium, particularly just above the surface of the water.  It is the “chloramines’ in the air which produce the common “chlorine smell” often experienced at indoor aquatic facilities if not treated effectively.  They have been shown to cause health problems, particularly in people with respiratory problems such as asthma.  These supplemental sanitizers are also effective as sanitizers, even though not permitted as a primary means.  These systems include:

  1. Ultraviolet Light (UV)
    1. Reduces combined chlorine (chloramines). Indoor air quality will improve.
    2. The frequency of super-chlorination of the pool is reduced with UV installed.
    3. UV is highly effective against chlorine resistant pathogens like Cryptosporidium and Giardia; as well as the vast majority of bacteria, viruses, yeast, and mold.

i.      Chloramines reduction: < 0.2ppm

ii.      Disinfection: > 99.99% for Cryptosporidium and E. coli.

  1. Medium pressure.
  2. Need to budget $1,000 per year for bulb replacement.
  3. Ozone
    1. Reduces combined chlorine (chloramines). Indoor air quality will improve.
    2. The frequency of super-chlorination of the pool is reduced.
    3. Full DIN system treats 100% of flow – very expensive
    4. Sidestream Ozone system treats approximately 25% of flow – still very expensive.
    5. Ozone systems are very complicated to operate – need pool operator that has experience with Ozone.


The sanitizers discussed in this overview have a high pH and thus raise the pH of the pool water therefore it is necessary to add pH buffers to lower the pH levels of the pool.  The options available are:

  1. CO2
    1. CO2 (Carbon Dioxide) is a pH balancing chemical that is effective with “soft” source water.
    2. Used when the total alkalinity is less than 70 ppm. CO2 raises the TA in the water.
    3. CO2 is injected into water to release oxygen and carbonic acid.
    4. No fire rating is required.
  2. Muriatic Acid
    1. 31.5% solution of hydrochloric acid.
    2. Muriatic acid reacts with the sanitizer, thus counteracting the pH, raising effects of the sanitizer. It has a pH of approximately 3. In the pool, it will lower the pH and total alkalinity. Typically delivered in 15-gallon carboys.
    3. Muriatic acid (hydrochloric acid) is classified as a corrosive and is highly reactive.
    4. Muriatic acid is used where the total alkalinity in the source water is above 70 ppm.

Pool Dye Test

When you jump in a pool you assume the water is clean, chemically treated, filters, and safe…everywhere.  I’m not just talking about the water near the inlets or around the main drains, I’m talking clean and safe water everywhere in the pool.  Have you every stopped to wonder if there’s a test to ensure adequate distribution of water circulation in the pool?  Well some jurisdictions require a visual test to prove each pool is without a “dead spot” of water, even the Model Aquatic Health Code references (section dye tests as a means to “…evaluate the mixing characteristics of the recirculation system.”  But what does this look like and how does it work?

After a pool is constructed, and prior to receiving operational permit, a non-permanent, non-staining colored dye is added to the pool’s surge tank or skimmer systems.  Almost immediately, dye will be seen returning through the pool’s inlets.  The pool will quickly turn a purple hue and you can easily see how all the water distributes within the pool.  After approximately ten (10) minutes, the entirety of the pool should be colored and the test is complete.  A short while thereafter, the dye will disappear when chlorine is added back into the pool.

For those who would like to test your own facility, this is an easy visual test to ensure you’re providing a safe and chemically treated aquatic experience for your patrons and staff.

Enjoy this time lapse video of a facility in Europe testing their facility.

You’re Not Alone! Facing and Fixing Today’s Aquatic Challenges

As the president of the North Texas Aquatics Association, I recently surveyed our membership of aquatics’ professionals in the Dallas/Fort Worth area, as well as some of my colleagues on the World Waterpark Association’s Public Sector Committee, in order to find out what challenges and obstacles they currently face.  As the results came in, I quickly realized that the majority of the challenges mentioned fell into one of three categories: Personnel, Financial and Facility.  And while none of the answers surprised me, it was interesting to see the challenges they face and how it affects them and their organization.

Staffing issues top the list of challenges, mainly because of the nature of the positionsCapture and hours offered to prospective employees.  Operators need staff from 5am to 10pm Monday through Friday, and most the day on the weekends too.  Not only that, sometimes staff is only needed for a few hours at a time (programming, noon lap swim, etc.) and it’s difficult to find dedicated and engaged employees who want to work a staggered schedule.  Because of this, employee turnover and competition from other less stringent jobs stood out as primary challenges posed to the group I surveyed.  Throw in the lack of buy-in from younger employees, and the complexities with recruiting, training and motivating staff, and aquatic professionals have a difficult task ahead of them, and we haven’t even gotten past the first category!

On the financial side, challenges included the rising costs of equipment, supplies and labor, something I noticed over the course of my days as a public sector operator.  From 2007 to 2014, the cost of my calcium hypochlorite went from $166.00 for 100 pounds to $193.00, that’s a 14% increase during times of shrinking budgets. Couple rising costs with aquatics’ staff being given unrealistic cost recovery goals for their facility and the decrease of annual operational budgets, they quickly become frustrated because they must generate more revenue, with less resources to do so.

On the facility side, operators struggle with maintaining aging facilities at an acceptable level, while not having the financial means to make it happen.  Aging pools built in the 1970s and 1980s face physical (aging infrastructure) and functional (lack of features) obsolescence.    These facilities have low attendance because which puts revenue generation at an all-time low, yet their costs keep rising.  Add in changing codes and legislation and now operators are being asked to patch their 40 year old pool to get it into compliance, when it needs a complete renovation.

Now, that we have a list of chalI Thinklenges that hinder aquatics’ professionals, let’s develop a framework to start tackling these one by one.  Anytime I look at overcoming a challenge, I asked myself four questions in regards to that specific challenge.

1)      What difficulties does this challenge pose?

2)      How does it affect my organization and operation?

3)      What are the benefits of overcoming this challenge?

4)      How do I overcome it?

Answering the above questions will make the path to conquering your challenges much easier and will provide you with clear direction and purpose.  Let’s take training and motivating staff as an example and then I’ll send you on your way to tackle the rest.

1)      What difficulties does this challenge pose?

Aquatic operators lack the time and resources to fully train their staff, primarily because they have so many other responsibilities.  Recruiting, hiring, programming, payroll and maintenance all take time and which leaves little time for training. Lack of funding also impacts training and motivation because training funds typically go first when budgets get slashed.

2)      How does it affect my organization and operation?

The lack of training and motivation means that operators receive poor employee behaviors which can put your guests at risk, as well as providing them poor service.  Without training, employees are less likely to buy in to the vision and culture of your organization, which means they leave sooner and operators have a high employee turnover rate.  That puts you back at square one which means less time to train and motivate because must spend time recruiting and hiring.

3)      What are the benefits of overcoming this challenge?

The benefits of training and motivating staff far outweigh the time and resources it takes because once you start training then you can become more efficient in your time management.  You can delegate some of your responsibilities to your more proficient staff and the good behaviors starts to flow from your team. You now have a safer facility with employees who provide better overall service.  They start buying in to your philosophy and vision and now they stay longer, which reduces your turnover and gives you more time to focus on improving your operation, instead of just getting by.

4)      How do I overcome it?

This is probably the toughest question to answer when looking at overcoming the challenge of training and motivating staff, but it’s also the most important.  Operators should create a training calendar that covers all of the topics that need addressing on a daily, weekly or monthly basis with each of their levels of employees.  Once complete, you must show the importance of training in order to achieve your organization’s vision (don’t forget to make attendance mandatory!).  Also, make sure you hire hiring individuals who have shared values with your philosophy, a positive attitude, internal motivation and great communication skills.  These are the ones that are easy to train!  I might take a little more work upfront during the hiring process, but you’ll be glad you did.  Training is merely an extension of the hiring process so it’s important to show organizational purpose and vision in the interview, as well as every day on the job.  Lay out your expectations on the front-end of employment, communicating to them what to do, how to do it and why it matters.  Buy-in, loyalty, staff retention and employee engagement await around the corner!

Overcoming challenges and obstacles can prove to be a difficult process, but a worthwhile one.  Improving your operation just a little at a time will have big rewards for the future and set your organization up for success for many years to come.

Cloudy Water Solutions Checklist

It’s that time of year again and as the summer season starts up many operators will have to deal with a nemesis to aquatic professionals around the globe, cloudy water! Before you just throw in some clarifier, here’s a quick checklist of items that you can take a look at if your water clouds up.

Fort LuptonWater Chemical Balance is typically the first thing that operators should check.  Start by checking the saturation index to see if your water is scaling or corrosive.  Next, ensure that you have enough chlorine in the water to effectively sanitize and oxidize, and also maintain your pH levels in the 7.2-7.4 range.  As pH increases so does the devaluation of your chlorine’s effectiveness. Cyanuric acid levels should also be checked and kept lower than 20ppm.  Too much cyanuric in the pool can cause cloudiness fairly quickly, as well as devalue your chlorine.

A second item to check is your chemical controller to make sure it is giving adequate readings.  Controllers should be calibrated on a regular basis and checked against the numbers you get when you are hand-testing the water.  If the readings are off then it’s either time for cleaning the probes and sensors, recalibrating them, or it might even be time for replacement.

The surface of your pool can also contribute to cloudy water, especially at the start of the season when it has sat empty all year and been exposed to the UV rays from the sun.  Painted pools can chalk at the beginning of the season so it’s always good to give them a good brushing before the pool opens to get all of the loose material off the bottom.

Bather load is obviously a huge factor since most of our pools don’t cloud up when we don’t have people in them.  If you think bather load is your problem, pay close attention to when it starts to cloud up and how many guests are in the park at that time.  You always want to ensure you are not exceeding the maximum capacity of your facility, and not putting your guests at risk.  If at any time the water is too cloudy to see any portion of the bottom of the pool, then you must clear the pool.  Guest safety is the utmost of importance.

Pool Filtration is another item on your list to check, though this is probably one of the hardest to diagnosis and fix, especially during the middle of your season.  You always want to dYuma, AZ (2)ouble check your flow rate and turnover to make sure they meet state codes, as well as meet the needs of your specific operation.  Debris can’t get filtered out of the pool if it’s not getting back to the filter in a timely manner.   Backwashing shouldn’t be done once a day just because; rather, it should be done based on the pressure differential on your filter.  Remember, a dirty filter traps more dirt and debris than a clean filter does.  Finally, put together a plan to observe, examine and replace your filter media per the recommendations of your filter manufacturer.  Over time, your filter media can definitely lose its effectiveness.

Hopefully, you won’t have to experience cloudy water at your facility this summer.  If you do, the above list is a great start to get you well on your way to finding the right solution.