Lighten up the pools: underwater pool and spa lighting in aquatic centres

Form and Light Pty Ltd

By Dr Walter Wendel*
Wednesday, 11 February, 2015

Lighten up the pools: underwater pool and spa lighting in aquatic centres

Let’s face it: without lighting, even the most beautiful pool would not stand out at night. But even during the day, pools and spas in aquatic centres and water parks can look quite dull without good decorative and functional lighting.

So, what is the purpose of the lighting? Basically, we can break it down into three categories:

  • Functional lighting: illuminating the pool surrounds and other areas of the aquatic centre or water park.
  • Beautification of the pool, spa and surrounding landscape.
  • Safety for swimmers.

The most neglected lighting for public indoor and outdoor pools and spas is the underwater lighting, which is the primary focus of this article.

Case study: Carpesol Aquatic Centre

Let’s use, as an example, the Carpesol Aquatic and Recreational Centre in Germany. The €19 million (AU$27 million) project was opened to the public in mid-2013 after a 21-month construction period. It combines training pools with leisure pools and saunas, creating a space where swimmers can be active or just relax. With 10 different pools and spas, four saunas and one steam bath, the centre has something to offer everyone.

In order to create the right atmosphere, coloured RGB lighting was used extensively within the pool, as well as throughout the surrounding areas. With the availability of LED light sources, coloured light and light changes are easily managed. With DMX controlled lighting, it is easy to achieve the desired results as the controllers can be programmed to set and recall static and dynamic scenes.

Image 1 (below) shows the powerful 85 W RGB underwater LED lights in the pool, smaller 28 W ones in the fountain and surface-mounted spotlights in the upper half of the dome. For the fountain and dome illumination, different colours are used in comparison to the pool and the surroundings to achieve a colour contrast. With the help of the DMX controllers, it is easy for the operator to adjust this.

Image 1.

Image 1.

For the large outdoor pool, powerful 115 W RGB LED fittings were used to illuminate the pool, with the side effect that the stray light from the pool illuminates the adjacent building. (Images 2 and 3.) The lighting designer chose a wide light beam distribution and as a result a homogenous illumination was achieved. With the high-wattage LED fittings, the illumination levels are elevated without any dark spots. This also gives the added advantage of ensuring clear visibility of swimmers at night.

Image 2.

Image 2.

Image 3.

Image 3.

These pool and surface mounted lights and the colours are controlled from a remote location, and preprogrammed scenes can easily be set by the operator. Settings include a slow automatic transition from one colour to another, and a static coloured scene setting. Choosing correct light beam spreads, suitably powered light fittings and a user-friendly control system was of utmost importance to the project. This would not have been possible with halogen lamp technology that was widely used until some years ago.

The availability of long-lasting and energy-saving LED lights paves the way for a true ‘fit and forget’ solution. A typical quality LED fitting has an L70 rating of 50,000 hours, which means that the original light output will reduce to 70% after 50,000 hours. To put this in perspective, 50,000 hours is equivalent to 11.5 years of operation, 12 hours a day - and the light is still working after all that time.

Underwater lighting considerations

For underwater lighting, it is fundamental to choose:

  • quality fittings made of 316L stainless steel to avoid corrosion problems like tea staining;
  • good-quality, specialised underwater cables;
  • fittings designed to ensure long-lasting watertightness.

These material requirements are not only important for the fitting itself, but also for the installation housing.

In regions with high temperatures and in saltwater and seawater pools, it may even be necessary to use higher alloyed steels such as 904L to avoid discolouration of the 316L steel.

Given the life expectancy of LED fittings, the connected electronics must also have a similarly long life. The use of quality, long-life drivers and controls is important as well.

Another consideration for pool lights in public aquatic centres is the location of the fitting with regards to the pool wall. Fittings that jut out from the wall are often used by swimmers as a step to exit the pool - a common occurrence that damages the fittings. Using pool lights with recessed, flush-mounted fittings with a thin rim thickness solves this issue. This type of fitting is also necessary for pools with moving floors.

To avoid glare, careful planning of the positioning and light beam direction in and above the water is essential. This can be achieved by directing lights away from the main public areas.

Lighting design

With regards to the lighting design, several parameters need to be considered to achieve the desired lighting concept:

Light colours for white light: warm white, cool white or daylight

Daylight white is a bluish white that creates a crisp colour rendering. Warm white, on the other hand, is more yellowish and looks like a halogen lamp light. Cool white is in between. In most cases the daylight white colour is chosen but the others can be more appropriate, depending on the pool surroundings. (Image 4.)

Image 4: (L-R) warm white, cool white and daylight white.

Image 4: (L-R) Warm white, cool white and daylight white.

Static solid colours

Blue is a popular static solid colour because it resembles the ocean under bright sun. However, green can also be suitable for some pools. In the past this was achieved with halogen lamps and colour filters; nowadays, the LED fittings in most cases don’t need a filter anymore. Even without filters it’s possible to achieve more light or use less power.

Changing colours

RGB (red/green/blue), RGB-W (red/green/blue/white) or RGB-A (red/green/blue/amber) is the LED technology for light fittings with changeable colours. Single lights or groups of lights can be set to static scenes or dynamic, playing a programmed scene. With RGB-W you get a true white and all possible colours; with RGB-A, a fuller colour palette with saturated warm hues is achieved.

Newly available LED fittings with multi-colours make it possible to produce hundreds of colours from one fitting. Better-quality light fittings can be controlled with DMX signals, which is a standardised signal and therefore can be connected to any DMX controller. From simple wall-mounted controllers, remote controls and to computer run controls, everything is possible. In most cases, a choice of different set scenes and one or two dynamic scenes is all that is needed. This can be easily integrated with the landscape lighting and also effect lighting for common areas.

For a demonstration on controlling an RGC installation with static and dynamic colours, visit

Light beam spreads

These include: spot (eg, 10°), medium flood (30°) or wide flood (60°).

With the available choices of different beam spreads, very different effects can be achieved. A couple of underwater spots with a narrow beam spread can create dramatic results with beams shooting through the water. Flood lighting allows homogenous glow throughout the pool without any dark spots. The result is a very different, dramatic effect with narrow beam spots or an elegant effect with wide flood fittings.

Narrow flood light distribution. Medium flood light distribution. Very wide flood light distribution.

Typical narrow, medium and very wide flood light distributions can be used to achieve very different effects.

Oval beam spreads for shallow pools

These include, for instance, 45° x 15° spreads.

An oval beam spread is very useful for shallow pools. In this case, the 15° is used in the vertical plane and the 45° in the horizontal plane to avoid light losses caused by the light hitting the floor and the water surface too early, then travelling through the water.

Multi-optic spreads for high-power lights

These can have floodlights and spotlights integrated in one light - a light fitting with two different integrated light optics in one light.

A beam distribution with two superimposed beam spreads is very useful for big pools, where high LED wattages are required. The flood characteristic illuminates passing swimmers close to the fitting, whereas the spot reaches far into the pool.

It is not always necessary to use powerful lights to illuminate the entire pool. For smaller pools and spas, one option is to install small lights that are decorative but don’t illuminate the water. In these cases, 1-5 W LED fittings are all that is needed. In the same category of decorative pool lighting are waterproof LED strips with IP67/68 ratings - again, more decorative than illuminating. These special LED strips are also available in all whites and RGB. They can be used as a slim, linear, decorative element.

Safety and visibility

A last word about pool safety and visibility: A common problem for indoor pools is that the general lighting above the pool creates reflections on the water surface. Therefore, it is often difficult to see below the water’s surface and identify swimmers that might be in trouble. Good pool illumination can drastically enhance the swimmer visibility for visitors and lifeguards.

Lighting in aquatic centres and public pools plays a role not just in functional general lighting but also the beautification of the pools, spas and surroundings. Illumination plays an important role in the venue’s overall appeal and can even increase swimmer safety.

*Dr Walter Wendel is the Managing Director of Form and Light Pty Ltd and is an authorised distributor for WIBRE pool lighting. Walter holds a PhD in Physics and Economics and has more than 25 years’ experience in the lighting industry. He has worked as an independent lighting designer, Product Manager for OSRAM in Germany, VP of Marketing for OSRAM-Sylvania in Canada and CEO of OSRAM Australia.

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