Correct chemical balance for a vinyl lined pool

Getting the water balance right in a vinyl lined pool is a little different to a pebble, tiled or other finished pool. Regardless of whether it is an above ground pool or an inground pool, the water in a vinyl finish pool all needs to be balanced and stabilised, and regularly checked for imbalances. The following levels ensure the best care for both your family and your pool, for a vinyl lined /Aqualux finished swimming pool. DO NOT use these levels on any other pool finish.

Recommended levels for a vinyl lined/Aqualux pool:

pH…………………….. 7.4 – 7.8

Total Alkalinity……  100 – 150ppm

Calcium Hardness..  200 – 400ppm

Free Chlorine……… 1 -3 ppm (non heated pool)

2 – 4 ppm (heated pool)

Stabiliser…………..  30 – 50 ppm

Saturation Index..  -0.1 to+0.4

Is there a special type of liner for an indoor pool?

 If you are renovating or installing a new PVC lined indoor pool, consider the type of PVC liner you are using.

Some people say all liners are the same, with the only difference being thickness, but that’s just not true. Most liners are made from a PVC film. This flexible, stretch fabric relies on the structure of the pool, and the weight of the water to maintain its shape. This works well in most situations, and with high quality options available, it’s an excellent surface finish for both above ground and inground swimming pools that are outdoor.

However, under certain environmental conditions (likely to be found in an indoor pool) the fabric of a standard PVC liner can sometimes start to ‘absorb’ water.

PH, total chlorine levels, ventilation and bathing load are all thought to be contributing factors. If the liner fabric begins to absorb water, it eventually expands the PVC, which then causes wrinkles to form in the pool. The wrinkles usually start on the floor of the pool, but can be all over the whole liner. If you look closely at a section of affected PVC, you can see the surface is weakened, and prone to forming tiny cracks that can develop into larger tears.

If this happens, there is no reversing of the process, and the life span of the liner is greatly reduced.

While many indoor pools are surfaced with standard PVC liners without any problems, there is always a risk of it occurring in the right (or wrong) conditions, and it is best to avoid the risk completely in indoor pools, by using a reinforced liner.

AquaForce is a specialist reinforced PVC fabric which is suitable for use in indoor pools. AquaForce features an internal reinforcing layer that keeps the fabric stable in indoor pools, and virtually eliminates the risk of wrinkling.

With a three layer design, AquaForce has a PVC base ply, a layer of reinforced polyester mesh, then topped with another ply of PVC. All three layers are homogeneously bonded together during the manufacturing process to be permanently fused. The mesh reinforcing layer stabilises the fabric and stops it from shrinking or expanding. 

Traditional PVC liners can be delivered to site fully welded in one piece, but AquaForce reinforced PVC liners are always fabricated on site, as they do not stretch or form to the pool shape.

The rolls of the AquaForce fabric are laid in the pool and overlapped to form seams that are welded on site. Edges are then sealed, to stop water absorption through the fabric itself. AquaForce liners can be fitted to any pool shape, as the liner is cut and shaped in the pool on site, allowing it to be fitted over steps and benches and down into deep ends of all style of pools.

 So if you are looking to install a PVC liner in an indoor pool, we recommend the use of a reinforced PVC such as AquaForce, to reduce the risk of wrinkling. AquaForce is also recommended for use on Commercial PoolsIndoor commercial pool, bunbury WA AquaForce liner.

Why is my new pool liner slippery?

This question has come up a couple of times in the last week, so I thought it was worth another mention. It can affect both inground pool vinyl membranes, and above ground pool liners.

Both are made of a PVC, which contain additives to make the material more flexible, to assist with with the rolling and processing during manufacture. These additives (known as ‘lubricants’) will sometimes sit on the surface, and make the pool liner feel rather slippery. While most people who are coming from a rough surface such as pebble are simply delighted with the texture, those who are replacing an existing liner will often feel that the new liner is too slippery. The slippery feeling is generally accentuated with replacement liners, as older liners often have small amounts of calcium build up on the surface, giving a slightly rougher texture.

The good news is that the slipperiness is only temporary, and the extra lubricants will ‘wash off’ the surface of the liner within 6-12 weeks, leaving you with the feeling of more grip underfoot.

If your pool liner is not a new installation, the most common cause of slipperiness is algae. Algae is incredibly slippery, and it is not always visible to the eye – just because you can’t see it, doesn’t mean you cant feel it!

So if its not a brand new pool, check your chemical balance. Chances are, it’s a little out of whack, and you have some algae. For the correct chemical balance for a vinyl pool interior, please refer to our Care & Maintenance document for vinyl pools  and print a copy for your records.

So if you find your liner to be more slippery than expected, check the chemical balance of the pool and ensure this is correct. If it is not due to the chemical balance, but your liner is brand new, then you will find after a few months the liner will have more grip under foot.

What are the pink marks on my liner?

It does not happen very often, but sometimes a pool liner will display some pink coloured marks. These are usually on the floor of the pool and will look “cloudy” rather than have defined lines or shapes. The pink colour is more commonly seen on a liner that has a white base and it is what we call “microbial staining”.

It seems to affect about 1 in every 500 pools, so while it is uncommon, it does happen. What causes it? Following heavy rain, pools in an area with a high water table can get water pass behind the liner. If this water contains certain microbes, and these microbes feast on the nutrients in the water, they will excrete small deposits. Those ‘deposits’ are acually a dye, and these dyes can move through the PVC and create cloudy stains on the inside of the pool liner.

This problem is purely site related and has no relationship to the batch of pool liner fabric or the colour of the liner or the person who installed it in the pool. It just happens when the ground water brings with it these nasty microbes, who in turn discolour the liner.

The good news is the liner is not affected in performance or longevity. The dye has just changed the colour a little and the pool will remain fully functional and easy to maintain as always. The microbial staining can disappear after short while if the ground water drains away from behind the liner and the stain will slowly fade.

Be careful if your pool chemical supplier advises you to “double the dose” of chlorine as you can damage the pattern or colour of your pool liner. (While this technique has been known to reduce the stains, it is most certainly not recommended).

A product called “Copperas Iron Sulphate” has been suggested as a remedy for this problem and is a much better option to try.

Apply the Iron Sulphate by using around 5Kg’s for an average 9mx4m pool. It is applied by sprinkling it around the pool surround (on all sides) and then watering it well into the ground with a sprinkler. Allow it to soak in and get down to the ground water around the pool over the next few days. This process is designed to change the ground PH to a level that will kill off the microbes and stop the dis-coloration of the pool liner. Be careful not to get the Iron Sulphate on paving areas as it can stain concrete and other paving products.

The Nylex formulation will not be lost!

One of Australia’s most iconic brand names, Nylex, has recently gone into receivership and parts of the business have been sold off or liquidated.

The “Films & Fabrics” division which manufactured Pool Liner material and many industrial and domestic fabrics was liquidated, and has now stopped manufacturing.

One of the saddest aspects of this is that PVC (vinyl) film will no longer be manufactured in Australia, as Nylex were the last (Australian) volume manufacturer of this product. Nylex had so much experience in all their years of manufacturing PVC film, that I believe their knowledge and formulation of PVC for the harsh Australian climate made their product the best performer by far.

What does this mean to the Pool, Tank and Geomembrane industry going forward? Well, there was a chance that these tried and tested material formulations (or recipes if you like) would be lost forever, but thanks to the efforts of a few local companies, some of these proven products will continue to be available.

The Aqualux and Aquaforce pool liner products have now been taken over by a company called Swimlinings P/L, and will continue to be produced exactly as per the Nylex formulation. So even though the Nylex brand is no longer involved, the actual product that we know and trust will continue to be available, and will remain true to its original ‘recipe’.

How long should a pool liner last?

Have you noticed in recent years the trend here in Australia and New Zealand toward an increased life span of (locally made) inground and above ground pool liners?

Does it make you also wonder, “How long should they last”?

In the past few years, large numbers of medium and large sized above ground liners have been imported from China and sold into our local market. And, it shouldn’t be too long now till we see how well they really perform in our harsh climate! As an educated guess, it’s likely they won’t last anywhere near as long as the Australian made liners.

I’m sure consumers are happy with many, many years of use from a locally made liner, but does this limit the opportunity for pool owners to update their pool look because the liner lasts so long? If my car exterior and interior looked as good after 10 years as it did the day I purchased it, I would be less likely to update it every 4 years. But as I drive it each day, the carpet looks a bit worn and the door trims have those scuff marks from the bottom of my shoes. You get the little dents and scratches on the doors from parking at the shopping centre and so you decide its time to upgrade.

This poses the question, “Would a pool owner be happier with a “new look” to their pool more often”?

Would they like to update the look of their pool to match current trends, as often as they change their furniture or paint their house? Or are pool owners deterred from updating their pool because there is plenty of life left in their pool liner and so they opt out because the current one is still doing the job?

My view is that you should expect a pool liner to last around 8-10 years for an Above Ground pool and 12-15 years for an Inground Pool Liner – but I know from experience that many last much longer. What do you think? How long should an Above Ground Liner last? How long should an Inground Pool Liner last?

Message me your thoughts…

Fact #3: Wrinkling of Liners in Indoor Heated Pools

The strangest phenomenon I’ve seen in my thirty-something years in the liner business is “wrinkling liner material caused by indoor heated pools”. If you read my recent blog about chemical levels you would conclude that this problem relates specifically to imbalanced pool chemicals, but this is not the case from my experience.

It first started in the 80’s when a customer contact us to say the pool liner in their 50 metre long pool, had grown about one whole metre in length. I almost didn’t believe them, so I went to see it for myself.

When I inspected the liner, sure enough, there were wrinkles and folds of liner all over the floor of the pool. It looked like the reverse of a dry creek bed, instead of open cracks, these were folds of PVC in a random crazed pattern. After a lot of investigation by the fabric manufacturer, the conclusion was that this phenomenon was a reaction to a pool environment that was made up of the following factors:
· Indoor
· Heated
· Commercial use
 (like a training pool or public pool)

Another case which proved the validity of the study result to me, was a school pool in a cold climate. It was built as an outdoor pool and used for two years without any noticeable liner growth. Then, the school decided the pool would get more use if it was covered, so a new building was built over the top of it. It became an indoor heated pool and within one year, the liner had grown to have large wrinkles all over the floor.

How can this be? What happens is, under these conditions, the PVC absorbs water and therefore expands. The expansion becomes visible as wrinkles and there also appears to be deterioration in the strength and flexibility of the PVC; in severe cases I have seen cracking along the creases.

Different solutions were trialled like, maintaining a level of cyanuric acid (not normally needed for an indoor pool), using a lacquered fabric, using a printed fabric, yet nothing solved the problem and so it was concluded that unsupported PVC was not suitable for pools with these environmental conditions.

The fabric manufacturers’ no longer provide a warranty for their PVC when used for this application and so it used at the risk of the Purchaser.

There are plenty of domestic pools that are heated and located indoors which do not show any problems, but many of the commercial pools under these conditions will exhibit the considerable wrinkling caused by this phenomenon.

Water balance and Vinyl Liners

Recently, one of my colleagues suggested I review an article about water chemistry and testing which focused on the effect of un-balanced pool water on vinyl liners. It concluded that balanced pool water has a major effect on the longevity of a vinyl liner in a swimming pool. I thought it important to pass on a summary of what was learned through the testing process.

We all know that water balance is important to the performance of the sanitising chemicals used in a pool, as well as for water clarity and comfort of the swimmers. However, water balance is equally as important for the life of your pool liner.

Using standard parameters of total alkalinity of 150ppm, calcium hardness at 100ppm and the starting concentration of cyanuric acid at 100ppm, a series of tests were conducted with different types of chlorine and PH levels ranging from 2.0 up to 10.0. Here is what was discovered…….

Samples with free chlorine at 1.5ppm where the PH was maintained between 7.0 and 7.5 (the Aust Std is 7.2 – 7.6) showed no adverse effects. The lower the PH dropped below 7.0, the greater the fading, wrinkling and loss of strength in the vinyl liner, plus it increased in weight (likely from water absorption which is what causes the wrinkling). As PH increased above 7.6 the vinyl lost weight and expanded. Samples with free chlorine at 20ppm where the PH was maintained between 7.0 and 7.5 showed colour change where white turned yellow and blue faded and became dull in colour. This high chlorine concentration caused wrinkling as well.

What this tells us is, it is important to maintain water balance to maximise the life of your pool liner. However, the study also revealed that even though the look of the liner changed with exposure to extremely bad chemical levels, the vinyl still remained functional as a pool liner!

Laser Measuring for Vinyl Liners

As a pioneer of Laser Measuring of Pools for Vinyl Liners, I thought I would share some guidelines on the type of measuring equipment available and where it is used. Firstly, assess what type of pool you want to measure to determine which device is required. Most pools are measured using a fibreglass tape measure which is okay for basic pools, but other devices are better when you have a lot of measurements or need to measure with more accuracy.

If you just want to use a laser device to measure A-B points and write them down, you can probably get a laser measuring device with +/- 2mm accuracy for around $200 from a trade tool outlet. This is a basic handheld device which will display the distance between two points but, in my view, is not all that useful when working with a lot of measurements. It doesn’t really save you any time because you still have to manually record each measurement, either on paper or on a computer.If you want to measure 2D style lined pools, capture the measurements on a device then download them to a PC or to liner order software. You can start with either a Leica brand “Disto” device which stores 1000 measurements to +/- 1mm accuracy, or a Hilti brand device. These handheld devices store the measurements on board so you can capture one or more pools of data and download them later onto your PC. These are a definite time-saver when working with a lot of measurements, but there are some limitations.

Let me explain…. One of the limitations of a handheld device is, exactly that, you hold it in your hand. This means your hand can move around and the laser point can easily stray off the desired target point in the pool. Ideally, you need a steady hand, or you may prefer to use a professional measuring instrument like a Total Workstation, as used by surveyors. These devices can be hired, but I recommend that you have sufficient training and experience before measuring a complex shaped pool for a vinyl liner.

For complex “3D” style pools, I suggest you engage an experienced surveyor to do the pool measuring for you. There are plenty of surveying companies around, but the key to a well-fitting liner is to ensure that the measured data points are located in the right place. This is something which requires the input from someone experienced in measuring pools for liners and cannot be left to the surveyor to decide by themselves. I recommend that you accompany the surveyor to site for at least the first ten pool measures to make sure they understand where you want the measurements taken. I suggest you mark the pool for the surveyor the first few times to help them understand where the seams on the pool liner will be located and therefore where the data points need to be. The pool liner seams are linked to the location of the data points so it is important the points are measured in the right spot, for smooth flowing lines through the pool.

You can download a 3D laser markout sheet from ABGAL’s web site which has more detailed information on what is required to measure these types of pools. ABGAL can also put you in contact with an experienced surveyor you can contract to measure complex 3D pools.

For information on handheld measuring devices please click here.

Seamless view – easy as 1-2-3

One of the criticisms in the past of vinyl liners for Inground pools was the seams. That’s all changed now! These necessary and integral parts of a liner cop a lot of flack from supporters of other pool finishes but they need not be a concern any more. In the past few years, the seams have been the focus of liner manufacturers and vinyl suppliers to minimise the number and make them look like they have disappeared!

Seams on printed pool liners were quite obvious due to the welding method that was traditionally used. Innovative manufacturer ABGAL pioneered a new type of welding technique for pool liners to produce a seam that was less obvious. This welding technique is called “wedge welding” and has seen an improvement in the look and even more importantly the strength of pool liners since its introduction.

A number of years later using its software design system, ABGAL offered a liner with the seams facing away from the viewing direction of the pool (usually looking from the home or entertainment area). This option meant liners could be manufactured with the seams positioned so they were “out of view” from most of the pool surround and has been a huge success.

Nylex, the only liner fabric manufacturer in Australia made changes to their printed pool liner fabric to improve the look of the seams in liners still welded using the old method. They have changed the backing colour of the PVC to blend in better after welding, giving a less obvious liner seam.

The latest innovation in seams again comes from ABGAL, they have developed what they call “Smart Seam Technology” which has reduced the width of the seams to half their original size, but retained all the strength of a full width seam, but looks so much better.

So, for a seamless view follow these 3 easy steps….. 

  1. Choose wedge welding for the liner
  2. Nominate the direction of the seams when ordered
  3. Use ABGAL’s “Smart Seam Technology”