Cast-In-Place Concrete Vs. Shotcrete: What's The Difference?
Wednesday, March 13, 2019
Today, the pool shell of a commercial swimming pool can be constructed in several ways. Two of the most commonly used methods are cast in place concrete and shotcrete. The major difference between the two is quite simply the method of placement. At the end of the day, both systems, with proper design and construction, will provide a rock solid pool shell which can last for more than 40 years.
Cast in place concrete construction can be a costly and very labour intensive process. This type of construction requires additional excavation to allow workers room to install an extensive forming system for both the inside and outside of the pool walls, which is used to contain the concrete and shape the pool structure. This working room behind the forming system requires backfilling when the concrete work is complete.
Once the formwork is in place, concrete is discharged from a ready-mix truck, and transferred to the work area by way of boom pump, line pump, buggy, or down the chute directly off the back of the truck. Next, concrete is placed on the ground or in the form work, and then must be vibrated for consolidation & compaction.
Cast in place concrete forming system.
Pouring cast in place concrete.
It’s the most common type of concrete construction.
Cast-in-place concrete will result in a strong and waterproof structure with compressive strengths of 4,000 to 5,000 psi.
When properly designed and constructed, cast in place concrete results in a relatively smooth surface that will require very little surface preparation for the use of epoxy-based pool paint, tile and plaster finishes.
Cast-in-place concrete results in the most uniform surfaces possible.
Over excavation is required to allow working area behind the forming system.
Very labour intensive to form the walls.
Backfilling of the formed walls is required.
It’s harder and much more complicated to form shapes.
Generally more expensive to construct in comparison to a shotcrete pool.
The quality of a shotcrete pool can be comparable to a cast in place pool with one exception. Typically, they do not require extensive forming which often results in cost and time savings. Although the hardened properties of shotcrete are similar to conventional cast-in-place concrete, the nature of the placement process provides additional benefits, such as very fast erection, particularly on complex forms and shapes, including curved walls. Due to the speed of construction and the minimal equipment requirements, shotcrete is a very cost effective building method.
The shotcrete method utilizes concrete that is discharged from a ready-mix truck into a shotcrete pump and then pneumatically “shot” in place against a wood or earth form. To increase the velocity of the material which improves the control of the “shooting” process, accelerators and other admixtures can be added to the nozzle along with air under pressure. Because shotcrete is "shot" up against wood forms or earth, there is generally very little backfilling required.
Pool form ready for shotcrete.
Shotcrete being "shot" into place.
No over excavation required. As a result there is very little to no backfilling required.
The ability to build in very tight spaces and “free form” applications make it very simple to build pools of any shape.
Higher compressive strengths than cast-in-place concrete. Typical compressive strengths of shotcrete are in the 6,000 to 7,500 psi range
Lower construction costs.
There are fewer trained and skilled in the use of shotcrete than that of cast-in-place concrete.
The finished surface of shotcrete is rougher than a finished surface of a cast-in-place concrete pool. Additional surface preparation is required before the application of epoxy paint. As a result most shotcrete pools have a plaster finish.
Movable floors and bulkheads are becoming more common in aquatic facilities throughout North America. Although they offer similar benefits to an aquatic centre, there is a big difference between the two options.
Movable floors change the depth of the swimming pool water, while bulkheads act as a divider in the pool. Adding a movable floor and/or bulkhead will create endless opportunities for many different programs and activities within one body of water. Imagine the difference a movable floor or bulkhead could make in your swimming pool!
With a movable floor system the programming opportunities at your aquatic centre expand; traditionally you would need numerous bodies of water to offer these types of programming:
Swimming lessons (0.5M-1.2M)
Lane Swim (1.1M-1.35M)
Synchronized Swimming (2.0M-3.0M)
Water Polo (1.8M minimum)
Aqua Cycle (1.0M-1.2M)
Water Walking Programs (1.2M-1.5M)
Physical Rehabilitation (Beach entry or 0.5M-1.5M)
Competition Training (1.2M-1.5M)
The photo above shows the movable floor at the new Guildford Recreation Centre in Surrey, B.C where the water depth changes several times a day in order to accommodate various programs at the facility.
The addition of a bulkhead at your facility can allow you to accommodate many different programs and activities individually or simultaneously! Large, single activity pools can be divided easily to create separate swimming areas for:
Swimming lessons, fitness programs and other aquatic classes
Swimming competitions, water polo competitions and other sports events
Diving and synchronized swimming
Other special aquatic programs
The photo above shows the bulkhead installation in action at the Roosevelt Park Pool in Rapid City, South Dakota. The facility includes a 10-lane, 50M outdoor pool and when the Bulkhead is in the middle park position, the pool transforms into a 20-lane pool! This pool also features water polo courses for both men and women.
MAKE THE RIGHT CHOICE
When choosing a movable floor or bulkhead manufacturer, it is important to consider the following:
What is the installation time and complexity of the bulkhead/movable floor?
Is the operation of the bulkhead/movable floor easy and user-friendly?
Are the maintenance and service costs low?
Are the metal parts made of non-corrosive 316 stainless steel or special bronze?
Does the bulkhead/movable floor offer an aesthetically pleasing appearance?
Movable floors and bulkheads offer the ultimate aquatic versatility for your facility. The addition of a movable floor to a swimming pool can make it simultaneously a deep diving pool, a child friendly shallow depth pool or a mid-depth pool for exercise and water games. The addition of a bulkhead can transform a large single activity pool into separate swimming areas for classes, sports events, or special activities. Installing a movable floor or bulkhead will increase water usage and maximize the swimming pools potential. One pool with unlimited possibilities!
There are a lot of considerations when selecting a swimming pool contractor to build your pool. Whether the project is a high-end residential project or a multimillion dollar waterpark, it is important to be very diligent in selecting the builder to avoid delays, cost overruns, improper construction and lots of headaches. But what things should be considered?
WHAT DOES THEIR SAFETY RECORD LOOK LIKE?
The safety record of a company should be a primary consideration. A company with a poor safety record attracts a lot of attention (not the kind they want) and can really bog down a project. In fact, a project can be put on hold for an extended period if there are glaring safety infractions or heaven forbid a serious injury or fatality on the job site. Ask the proponent for a copy of their Health and Safety Policy, and safety record. If they don’t have one, or are unwilling to provide information, move on.
PRICE ISN'T EVERYTHING
Price, while always an important consideration is not everything. We frequently hear our clients say “…I wish we had gone with the more reputable builder. This job has become a nightmare…” The saying “you get what you pay for” could not be truer. If the price seems too good to be true, it is. There is no such thing as an extraordinary $7 bottle of wine, and there is no such thing as an inexpensive Bugatti car. The two things are mutually exclusive. The Bugatti and a K-car will both take you to the store, but the Bugatti will take you to the store for decades (and look really good doing it!), and there is no comparing the quality of the two. The same is true in pools. You can choose a method and a builder that may appear to save you a little coin but suffer endless change orders and additions to the project. Or you can spend that little extra bit of money to hire a thorough and reputable builder and have peace of mind for years to come.
DO THEY HAVE A STRONG FOUNDATION?
Like a strong building, a strong company needs a strong foundation. In the construction business, this foundation is in the form of knowledge that is both deep and wide, and can only be acquired from years of experience specific to the industry. A newer business just doesn’t have the history to be as knowledgeable as a well-established company that has been around for a long time. In the experienced company, there are senior people and younger members of the team. There is a combination of high energy and drive and a deep well of information that was developed over decades of practice. The thing about knowledge is that it is often applicable to a wide variety of applications that help experienced builders provide the best outcome for the client. Hydraulic concepts in pools and water management for example, are often applicable to electricity where Voltage equates to Feet of Head and current flow to velocity. Companies who have a deeper knowledge in their art have a broader understanding of the many things they may encounter in performing their work. Look for contractors who have a broad range of experience over a long period of time, senior people who have “been around the block” a couple of times and young energetic and well educated project people.
DO THEY HAVE INTERNAL SYSTEMS IN PLACE?
It is a great thing to have knowledge, but if it is held by a few individuals it often fails to crystalize in the positive outcome of your project. Good companies develop internal systems that reflect the Best Practices that have been developed out of the knowledge gained from experience. It is these companies who seek to establish a culture of quality and caring expressed in writing the form of standard operating procedures. Ask your potential contractor if they have internal systems in place to support quality assurance, delivery, and value added designs, longevity of the product, and so on. A company with systems is a company that cares about what they do, and who they do it for. Also ask if the company has a Mission Statement. The Mission Statement is the guiding philosophy of the company. A company without a mission is like a pilot without a map. Yes, the plane is flying…but the destination is dicey.
WHAT IS THEIR EXPERIENCE LEVEL?
The Record of Experience speaks volumes about the knowledge base of the company. Obviously, the more pools a company has built, the more experience they have. But it is also important to look at the different types of pools that a company has built. Not all pool builders build all pools, and sometimes for good reason. For example, Company ABC may be an advocate for cast-in-place pools through their limited knowledge and experience; they know how to build them, but nothing else. Concrete pools are really good and are considered the gold standard in the industry, however, there are times when another type of pool is more appropriate than a concrete pool. If the pool is going on the top floor of a high rise, weight may be a limiting parameter. It is important to find a builder who has the experience to recognize and understand your options and what best suits your needs. Ask your potential builders for their list of projects (current and complete) and also for a list of references. If the record of experience is small or limited in scope, you may want to look a little deeper into the company. If the reference list seems small compared to the record of experience, it should raise a red flag! A good contractor doesn’t maintain a specific reference list…every single client should be a reference.
DO THEY USE THEIR OWN FORCES?
If the builder you are looking at using has a lot of subcontractors, it may be worth looking a little further. Dividing the scope into different trade subcontracts (mechanical subs, waterproofing, tile, concrete etc.) dilutes and displaces responsibility of the trades and of the general contractor. When something goes wrong, it’s nobody’s fault, and it’s everyone’s fault. A great deal of time is spent trying to figure out if the waterproofing contractor caused the leak, or if the tile contractor damaged the waterproofing. Or maybe the concrete contractor is at fault. It is best to source a contractor who self-performs the entire pool scope with their own forces from the excavation, to mechanical and electrical work, to tile setting and commissioning and training. When there is only one company performing the entire scope for the work, there is no opportunity to cast blame for problems to others. You only have one phone call to make.
ARE THEY FINANCIALLY STABLE?
The financial stability of the company is also an important consideration. Are they able to completely bond a large project? Often tender documents ensure that this is the case, but private projects may overlook the need. What happens if things go wrong, or the contractor walks off the job or goes bankrupt? Who will finish the job? Who will pay for the work? Also, you want to be sure that the company you select is going to be around tomorrow and for years to come. Of course, there is never a guaranty but the best predictor of the future, is a record of the past. If the company has been building great pools for decades, they are likely to be around for a long time to come.
DO THEY HAVE A SERVICE DEPARTMENT?
Once the pool is built, you are away to the races. But what if something goes wrong with the pool after a few years? Who will close the pool for winter? It is always best of the company you choose to build the pool also has a service department who can deal with any problems and to perform regular maintenance. The service department of the company who built the pool is best equipped to service the pool since they will have an intimate knowledge of the pool from the construction phase. There are many “pool builders” out there who actually have no idea how to best operate a pool, and have no service department. It is best to steer clear of these builders. Once the project is complete, you never see them again.
CAN THEY PERFORM?
Finally, schedule can be critical, especially for commercial projects. Liquidated damages can cripple a business that was counting on opening the pool in December, but it didn’t happen until the following May. There has been more than a few projects abandoned or sold for pennies on the dollar as poor performing contractors drove the owner into insolvency. No builder is perfect or immune to making mistakes…things happen. What sets the premium builder apart from others is how they react to the problems. The only way to know how different builders react is to speak with their past clients. Don’t accept a short list of “preferred references”. It is a lot of work to fully research your builder, but it will pay dividends many times over in the long run.
A well-constructed pool delivered on time and on budget will provide decades of enjoyment, or in the case of a commercial project, revenue generation. The best start to this positive outcome is to balance all of these considerations discussed, and make a good decision.
Following construction, the commissioning of the pool system is critical to ensure that it is working properly and as it was designed, before handing over the operation of the pool to its Owner. These are the people who will be operating and maintaining their body of water on a daily basis.
During commissioning, all pieces of equipment are started-up, run, and programmed. I have learned first-hand how important it is to allow for the proper amount of time for this to occur. Allowing a few weeks to complete the commissioning ensures that each piece of equipment has enough time to operate as designed. If anything goes wrong it can be rectified immediately.
The set-up of the system begins when the water is introduced into the pool. Once the water starts to run through the piping, it is also running through each piece of equipment that is required to operate the system. Here are a few examples of equipment that requires set up;
The chemical controller, which monitors and reads the pools chemistry, requires some initial set up. The controllers parameters are set to ensure that if the chemistry is not within those parameters, the controller alarms to alert the operator that the water chemistry requires attention. This can take time to complete to ensure accuracy.
After the pump is started up, it should be allowed to run for a period of time to ensure that there are no leaks. Seals in a pump can be dry and cracked before the pump is even installed. You won’t be able to physically see this issue until the water is running through the system.
Those are just two examples of the numerous pieces of equipment that are involved in pool systems, most of which require set up. There is always a possibility that equipment can fail, so ensuring everything is commissioned by the time the system is fully operational means less chance of equipment or system failure. When there is a failure after the pool is fully operational, it could mean that the pool would have to be shut down and closed to its patrons. This is something that all Owners want to avoid at all costs.
Once the pool is completely commissioned, it is now the perfect time to train those individuals who will be operating the pool on a daily basis. Every pool system is different, so even if a person has experience with pool systems, the new system could be slightly different. A controller could be updated from the previous version, or the system could include a UV system that the Operator has no previous experience with.
Training sessions cover many techniques including:
How the piping system flows
How to operate the controller
Understanding what can go wrong
What to do if the pool overflows
How to adjust chemistry of the pool
What to do if the system equipment is in alarm
Allowing those people the opportunity to watch and learn through a hands-on training session has amazing benefits for them in the future operation of the pool. When Operators have the understanding and knowledge that they need, their confidence level is increased, allowing them to maintain the system properly, and promptly deal with any issues that may arise, shortening their down time.
As you can see, commissioning and training benefits all parties involved in the operation of the pool system. The time for this to occur should be considered in every construction schedule.
Pool water filtration is one of the most important aspects of a swimming pool. For obvious reasons, it is imperative that the water be clean and clear. Swimmers and lifeguards require this crystal clear water for several reasons, whether it be for swimming laps, knowing when to start a flip turn, or being able to see all of the pool patrons clearly in order to effectively monitor the pool. Furthermore, the water needs to be clean and free of bacteria so that swimmers do not leave with an illness. While there are many systems that work in conjunction with a pool filter to help keep the water healthy, the physical pool filter, which is available in varying styles and options, is the focal point in providing clean, clear water.
In most cases, pool water is pushed by the filtration pump through the filter system. Other systems operate using the pump on the other end of the system where it can pull the pool water through the filtering system. Either way, what happens is essentially the same – as water passes through the filter media, physical dirt and bacteria are removed, and clean water continues from the filter through the remainder of the recirculation system for further treatment, and returned to the pool.
The style of filter, along with the media being used, will determine the effectivness of the filtration system, as differing types of filter media actually filter different sizes of particles out of the water.
#20 SILICA SAND
The reason that pool filters use #20 silica sand (also known as 20 grit or 20 grain, 0.45-0.55 mm sized granules) is that it is small enough to filter out micro bacteria, yet large enough that it doesn’t get pushed through the whole plumbing system and cause other problems. In addition, larger granules are unable to filter the small bits of dirt and bacteria that it is intended to. #20 silica sand can filter out particles down to 20-40 microns in size. As water passes through the sand (which is essentially a really small stone, which is jagged on all edges if looked at through a microscope), the jagged edges catch tiny dirt and bacteria particles, eliminating them from the pool environment.
Depending on various factors (bather load, bather cleanliness, etc.) sand filters need to be backwashed every so often to clean the sand. If the sand filter is not maintained, it will stop filtering as it is supposed to. Backwashing is completed by running water through the system backwards to release all of the dirt and bacteria that has been caught by the sand, and must then be removed from the filter tank. When the water being discharged is clear, you are finished backwashing. Most filters have a sight glass so operators can physically see the dirty water at the beginning of backwashing eventually turn clear when the process is done.
Sand is the oldest and most commonly used filtration media, because it is effective and one of the most cost friendly options. However, after many cycles of filtering and backwashing, the granules become rounded, eliminating their filtering capabilities. The sand should be changed approximately every 5 years, depending on usage and backwashing frequency.
Zeolite is an all-natural product that is gaining popularity in the pool industry. It is about half as dense as #20 sand, meaning you can use about half as much as what is recommended for the filter. For example, if your filter requires 100 lbs. of sand, you would only require about 50 lbs. of zeolite. This type of filtration media is a bit more expensive than sand, so there will be a higher upfront cost. With the ability to filter particles down to 5 microns, Zeolite is comparable to a D.E. filter, and better than sand, though D.E. filtration systems are much more expensive than a sand filter system charged with a zeolite media. Zeolite lasts about the same amount of time as sand with regular use, which is approximately 5 years.
Crushed glass is a new addition to the filter media family. Made from recycled glass (good for the environment) that is crushed to the same size as #20 sand, it filters using the same principles as sand. In comparision to sand, crush glass lasts longer (approximately 10 years) and can help in removing micro particles with its negative charge. When using crushed glass, more of the filter media is used for filtering because it utilizes more of the filter tank, as opposed to sand which typically only uses the top four to six inches. This means there is a shorter backwash time, saving more precious water.
DIATOMACEOUS EARTH (D.E.)
Diatomaceous Earth (D.E.) filters the water very effectively, down to two to six microns, however they are more expensive systems and take up a larger footprint in the mechanical room. D.E. is tiny fossilized skeletons of sea plankton that are coated onto a grid of filter elements that sit in a tank where the pool water passes through. The water can either be pushed or pulled through this system. D.E. is considered carcinogenic, and proper handling and storage techniques, including protective gear and breathing protection, must be adhered to. D.E. filters are able to be backwashed for cleaning, but the media is lost in the process, and needs to be periodically replaced. D.E. systems do not eliminate chloramines which cause the chlorine smell commonly noticed at an indoor pool, so using a UV system is strongly recommended in order to eliminate them (a reccommendation for all pool filters).
Regenerative filters are another new option in the pool market. They also utilize D.E. or a synthetic substitute, however are a bit more complex in their design. In a traditional D.E. filter, only the channels and depressions of the surface of the filter media trap particles. The underside of the D.E., the side attached to the grid, has a reduced ability to filter. In a regenerative filter, the media is held on multiple tubes, or “fingers”, that are periodically “bumped”, causing the filter media to fall to the bottom of the tank. The filter media is then redistributed, allowing unused sides of the media to be used for filtration as well. Regenerative filters offer a large amount of surface area with a relatively small footprint and are often toted for their water saving qualities due to the reduced need for backwashing and D.E. replacement. The water savings may or may not offset the cost of these units, therefore your individual return on investment should be evaluated before purchase.
Thanks to several innovations and advancements in technology, there are many options available when considering pool filters, and filtration media. It is important to consider all of the factors specific to your project when choosing a filtration system, or to at least understand what you want and don’t want when planning with the pool designer that is working on your project. You want to have the right filtration system and media for the facility to ensure it is operating in the most economical way.
Heat Loss Prevention: Solar Blankets or Liquid Pool Covers?
Wednesday, July 11, 2018
When I think about heating an outdoor swimming pool, the first method that comes to mind is a solar blanket, or solid cover. Usually, this means a large blue bubble wrap sheet that covers the entire surface of your pool, and is stored on a reel when the pool is in use. However, did you know there is another option to help keep the heat in your pool? Let’s take a look at two of the most common, but different options.
A solar blanket retains heat, and radiates the heat to the pool water when the sun is shining. When purchasing a solar blanket, you have several options you can choose from including, but not limited to size, shape, colour, density, and type of material. With the array of sizes and shapes, there will always be something that will fit your pool almost perfectly or, in some cases, after a little trimming. All colour options are equally effective, so the choice of colour is ultimately based on the pool owner’s preference. The density of the cover will usually determine the life expectancy of the cover.
Solar blankets can help protect your pool water from debris that could blow in on a windy day; however, solar blankets can also become a breeding ground for algae if left on for too long in the heat and humidity. Below, are a list of some of the advantages and disadvantages of solar blanket heating options.
Solar blankets have an insulating quality (provided by the air pockets that make them up) that liquid covers do not.
Can help prevent some debris from entering the pool
Solar Blankets don’t last long. After approximately 3 seasons, the blanket will need to be replaced.
Labour intensive (If you do not have a reel for your solar blanket, you need two sets of hands to lift and fold the blanket before and after pool use)
Solar blankets are not aesthetically pleasing.
They can be very dangerous if trapped underneath.
Not environmentally friendly. Did you know you can make tens of thousands of sandwich bags from the material used in a solar blanket? Process to manufacture uses oil to produce the plastic.
Although a solar blanket will prevent some debris from entering the pool, most of it ends up in the pool when you take the cover off.
LIQUID POOL COVERS
Liquid covers reduce heat loss in your swimming pool by reducing evaporation of water from the surface. There are a number of liquid pool covers currently on the market by many different manufacturers. However, one thing that seems to be consistent throughout the market is the environmentally friendly factor. Liquid pool covers are usually biodegradable and made with an alcohol based product, which won’t harm your pools chemistry when used in the correct dosage. Most importantly, liquid pool covers are safe for your family, and even your four legged friends!
The ingredients used to form a liquid pool cover are not the only safety feature. When considering safety, liquid pool covers are by far the safer option in comparison to a solar blanket. If you have children or pets and use a solar blanket, there is a potential risk of entrapment. Once submerged, a solar blanket can be difficult to escape for people and animals of all sizes. A liquid pol covers invisible film is impossible for something or someone to get caught underneath, eliminating the risk of entrapment entirely.
When taking operation into account, liquid pool covers have their disadvantages as well. Since the liquid is a thin layer, it can be disturbed by movement in the water and from wind. The liquid pool cover will only resume its total pool coverage once the water movement has stopped.
The convenience of a liquid pool cover is another benefit. There is no labour required to use this product. On top of that, how many times have you thought to yourself, “I’d like to go for a swim”, only to realize that your solar blanket is on and to go swimming, you not only have to find another set of hands, but you also have to remove it? Sometimes, going for a swim isn’t really worth the effort. A huge benefit of a liquid pool cover is the immediacy. Do you want to swim right now? Great! With a liquid pool cover all it takes is a big jump and you are swimming, without the worry of lugging that large wet plastic tarp off of your pool. Below, are a list of some of the advantages and disadvantages of liquid pool covers.
The danger of entrapment is eliminated with the use of a liquid pool cover
There is no labour requirement
No need to worry about replacement covers
Very aesthetically pleasing. The cover is completely transparent, and invisible to the naked eye. Swimmers won’t even know it is being used.
Environmentally friendly and biodegradable
Must purchase the product
Not suitable for disturbed water
Will not stop debris from entering the pool
Solar blankets and liquid pool covers both have their benefits, but they also have their downfalls. They are both effective at preventing heat loss from your pool, however, there are some differences. After considering all of the factors for each option, and weighing them against some of your needs you can determine the benefits you value the most, which in the end, will help you make a decision.
Today, technology is all around us. It makes our lives easier and allows us to connect to anything from anywhere at anytime. Having a smart phone, access to the internet, and heck - even a personal computer, is a staple in this day and age. The internet is about to become classified as a utility because we are so dependent on it for our everyday life. When I was growing up, technology was nowhere near where it is today. There was no such thing as an iPhone, an Android phone, or a Blackberry. I remember the days when a telephone was attached to the wall, it had a rotary dial and a cord, and it meant running half way across the house to answer it when someone called! The extent of modern technology in my house as a kid was a microwave, a television, a VCR and an Atari game system. If I wanted to communicate with friends I had to either call them on the old rotary phone or walk down the street to their house.
Fast forward to 2016 and just imagine your life without technology. With app’s like Twitter, all of the day’s news is waiting for us in the palm of our hand each morning. With Facebook and Instagram, we don’t even need to call our friends to know what’s happening in their lives. Technology has so much to offer and it has reached out into most areas of our everyday lives making completing daunting tasks more efficient and less time consuming. If you look around, how many people do you see without a form of technology, whether it be a mobile phone, a tablet or a personal computer?
Well the modern day swimming pool is no different. Technology, automation, and computer controls play a very important role in today’s pools. Gone are the days of having to manually adjust the chemistry in a swimming pool by hand on a regular basis. Swings and spikes in pool chemistry were difficult to control when adjusting manually, but with the help of technology, computer controls keep the chemistry in check and allow your pool to virtually run on auto pilot.
These improved chemical controllers also add an additional level of safety to the modern pool. Given that the chemical controller controls the feed of chemicals into the system, it also has the ability to lock out the feed if chemical levels get to high or too low. For example, if the PH level in a pool drops too low, the water will become very acidic and can cause damage to the pool/spa, and can also cause irritation to a swimmers body. If the body of water is very small, such as in a spa, and PH levels are drastically low, it can even cause acid burns. When the controller sees a low PH condition it will put the controller into alarm and prevent additional feeding of muriatic acid, keeping bathers safe and alerting the operator through on screen displays, texts or email notifications. The controller can also do the same thing when it comes to chlorine levels. If the chlorine levels in a pool or spa become too high, it can lock out the chlorine feed until the levels come within an acceptable range. The controllers can be set to a proportional feed, pumping in smaller amounts of chemicals to prevent “over shooting” or “spiking” chemical feed.
Behind the scenes of every swimming pool is a mechanical room; the mission control of a pool. The mechanical room is full of pumps, filters, piping, heaters, controls, UV’s, and a small computer control center called the chemical controller. The chemical controller is the brain of the entire operation, but what does it do and what are the differences between the different manufacturers?
The chemical controller constantly monitors the water through a sample line and sample cell which is fed water via the filter pump. The basic controller is checking the chlorine or bromine levels and PH with ORP and PH probes. Higher end controllers also have the ability to check free chlorine, total chlorine and stabilizer levels. What’s more, they can also connect to and control UV units, start and stop filtration systems, automatically control backwashing of the filters and they can even communicate with variable frequency drives (VFD’s) and building automation systems.
The days of worrying about your pool while you’re off duty or away from your facility are long gone. With new technology, most chemical controllers now have the ability to send a text or email notification directly to your smart phone if the controller senses a problem! You can even connect to them over the internet through HTML or smart phone apps to monitor and control the complete system from anywhere in the world. Talk about a technological advancement for a swimming pool!
Imagine being a pool operator of a commercial facility and having an issue with the pool in the middle of the night, or worse, while you are away on vacation. You could come back to a real mess, and the pool chemistry could be completely out of balance. Depending on the size of the pool, this mess could take a couple of days to get back inline. A pool with a modern chemical controller will notify you of the problem and then automatically start to chemically treat the water to keep it in balance, before you come back to a big mess.
But what are the big differences between different manufacturers? Is one better than the other? In my opinion, there really aren’t any “big” differences; they all come down to budget, options, and operator preference. All name brand controllers come with the basic ORP and PH monitors and controls, and just like a new car you can get them with options. For example; if monitoring the chlorine levels and bromine levels by ORP is not your thing, add on a PPM probe. Some operators are not familiar with ORP levels, but they are very familiar with PPM levels because this is what they commonly record in their books. Is the ability to log in and control your pool using your smart phone from anywhere in the world important to you? No problem! Just add an HTML interface. Today, most chemical controller manufacturers are seeing the importance of being connected all the time and this option is now becoming a standard hardware option and just requires setup at the time of commissioning. Are you looking to monitor the cyanuric acid level of your outdoor pool? No problem! Simply add on the probe. Free chlorine and total chlorine are an easy add-on to any system with the simple addition of monitor probes. All of these options can be added to any chemical controller.
No matter what brand you choose, at the end of the day all will ultimately do the same thing. How much it will do depends on how much you want to invest and what options you want to include.
So next time you are staying up to date with your friends on Twitter and Facebook, or checking the news on your CNN app, take a few minutes to click the pool app on your phone and see how things are operating on your swimming pool.
Salt Water Chlorination: Is it the Right Option for your Facility?
Wednesday, March 14, 2018
Salt or no salt? That is the question! Or at least one of the most common questions being asked by pool owners and operators these days. Every pool owner has their own set of reasons for wanting salt or not wanting salt. There are many questions regarding the mechanical equipment at the facility, finishes of the pool, uses of the pool, local bylaws, (just to name a few) that must be answered before jumping to any decisions. Additionally, the owner must be aware of the many myths regarding salt water systems and chlorine systems alike before making any decisions. They must also understand that a salt water pool doesn’t mean you will be swimming in ocean water! Windows to the Universe team states that salt water pools typically have 3,000 to 6,000 ppm, while the ocean is about 35,000 ppm.
When changing a liquid chlorine sanitized pool over to a salt water system, or when building a pool destined to be salt water, the mechanical systems must be selected properly. Everything from the pumps, filters and heaters must be designed and approved for use in a salt water pool. If this is not done, manufacturers will not honour warranties, and there will be damaged equipment much prior to their normal lifetime.
The finishes of the pool need to be considered when contemplating a salt water pool as certain finishes do not last as long under salt water conditions. Liners, tile and plaster finishes all have their own issues when it comes to salt, so owners must investigate each option thoroughly and ensure whichever option is chosen is installed properly. As with any sanitation system, monitoring and proper balancing is also very crucial in the lifetime of the finishes.
Fixtures such as hand rails, underwater lighting fixtures, and rope anchors need to be properly chosen when going with a salt water pool as they will corrode faster without being constructed of proper materials and properly maintained. The image above shows a hand rail in a salt water pool that is rusting due to the salt. Think of what salt use on our roads does to our vehicles and infrastructure during the winter months. The same type of damage will happen to a pool that doesn’t have all of its components designed for salt water use.
Primary uses of the pool under consideration for salt water should also be considered. A pool that is primarily for lap and competition swimming where there is high swimmer volume and high exertion may want to shy away from a salt system, as it will require much more monitoring of the chlorine levels to ensure they are in accepted ranges. Yes I said chlorine. Salt water pools still have chlorine in them. They use a chlorine generator system involving a process called electrolysis to produce its own chlorine, rather than adding liquid chlorine directly to the water. A therapy pool with low patron turnover may be a better candidate for salt water, as it will be easier to keep the pool balanced and may increase user comfort.
Local bylaws are another very important item to look into when considering salt water in your pool. Especially for commercial pools, salt is typically not permitted to be the primary source of sanitation. Most municipalities still require salt water pools to have a secondary sanitation system installed, typically liquid or tablet chlorination. Furthermore, when draining the pool, salt (and chlorine) levels usually must be brought down to low levels in order to legally be dumped into the municipal sewage treatment system. Always check local bylaws for your stipulations prior to draining your pool.
Pool owners need to ensure that they do as much homework on salt water chlorination as necessary to ensure that they have made an informed decision. There are too many cases of owners not taking all of the necessary steps required to properly operate a salt water pool, and have a seemingly endless repair bill. As with any large expenditure, always ensure you are working with qualified pool designers and builders when constructing a new pool or doing a renovation, no matter what sanitation system you are going with.
When planning the construction or renovation of your pool, whether commercial or residential, one of the many decisions you will need to make is the pool finish. There are several options available to both commercial and residential pools, there are also many factors to consider when choosing a finish. Cost is usually the first thing on everyone’s mind, when making any purchase. However, there are many other considerations that will often times outweigh the initial cost. The intended use of the pool is an important factor to consider when determining the finish of a pool. Residential pools, which have a lower use, can get away with one of the more budget-friendly options, as there is less wear and tear. A low-cost finish will save some money upfront however, repairs and refinishing will be required much sooner than some of the longer lasting, high-end finishes.
Tile has been used as a pool finish for years and is known to be the most durable finish. When applied correctly, a tiled finish can last for decades before requiring any replacement. Tile offers the pool owner a wide variety of colour options and design possibilities. Due to the preparation and labour required for installation, this high quality finish option comes at a higher initial cost. However, over time it will pay for itself, through the savings on repairs and replacements.
Durability & Longevity: A tiled finish will last decades if applied correctly, and compensate for the higher upfront costs.
Easy to Repair: If there is an issue with isolated delamination of tile, it is very easy to replace small areas of tile and match to the existing, without having to re-finish the entire pool.
High Upfront Cost: Correctly installing tile, comes with heavy labour including; the preparation of the subsurface, laying the tile and grouting the tile.
Deterioration of Grout: Though tile has a very long life span, the grout will deteriorate much quicker. Over time grout will begin to wear out of the joints and discolour. Normally, grout will be required to be replaced much sooner than the tile.
Plaster is one of the most prominent pool finishes around, and has been used for several years; a quicker install than products like tile is the main reason for its popularity. Plaster is shot onto the pool walls, similar to gunite, and then toweled to give it a smooth consistent finish. A plaster finish does require some sort of tile border at the waterline as the waves against the plaster will cause it to deteriorate quickly.
Cost & Durability: Even with the high level of durability a plaster finish offers, the cost is relatively low.
Aesthetically Pleasing: Plaster provides a very nice finish which is smooth and able to form to any shape or design.
Pool chemistry can very quickly deteriorate a plaster finish if not properly maintained; low pH in the water is a big concern and requires experienced supervision.
With age, pool plaster will start to delaminate and cause sections of the plaster to pop off, having to re-plaster a pool is very costly.
Painting a pool is a very inexpensive method of finishing any pool, and is typically used in a commercial application for community or public pools. Though painting a pool is an economical and quick finish option, over several years the paint will chip and need to be repainted. A parge coat is required before painting to ensure all honeycombing of the concrete is filled, leaving the floor and walls smooth.
Low Cost & Project Schedule: The cost of the material and labour required to complete the work is extremely low and can be completed quickly.
Low Risk of Damage: Since paint is applied to a cementations backing, there are no concerns about damaging or puncturing the finish from items in the pool.
Frequency of Repairs: A paint finish will need to be refinished every 3 to 5 years, requiring the existing paint to be blasted off before repainting.
Imprefections: If the subsurface of the pool is not done perfectly any imperfections such as honeycombing or rough parging will show through and can cause injuries to swimmers.
VINYL LINER FINISH
Traditionally Vinyl liners have been a typical residential pool finish, due to the relatively low cost and quick installation. Liners can and have been used for commercial applications however, due to the low durability of a liner it is not very common. Vinyl liners can be used in both stainless steel and concrete pools.
Low Cost: In comparison to other finishes, liners can be an economical alternative. The liner itself is relatively inexpensive, in comparison, and installation labour is a significantly lower cost.
Creates a Water Tight Tank: This benefit can be an efficient solution, saving time and money, to a deteriorating concrete pool, which has started to leak.
Deterioration: Vinyl liners are more susceptible to deterioration caused by harmful UV light and poor water chemistry, resulting in the liner needing to be replaced sooner.
Easy to Damage: Vinyl liners can very easily be damaged from foreign objects, such as tree branches or toys falling into the pool. Punctures in the liner will result in water getting behind the liner, causing the pool to leak and the liner to bubble out.