The technique of the infinity pool
Overflow is primarily a hydraulic principle and it is useful to specify its main characteristics:
- Most overflow pools are built in concrete, although a few manufacturers of pool kits or shells have entered this market.
- An overflow pool is either in-ground or partially in-ground
- The filtration system installed in the technical room is very similar to that of a skimmer pool. The additional equipment is detailed below.
- All linings can be used: liner, reinforced PVC, polyester, tiles, …
The quick schematic diagram below will help you to find your way around easily, without having to use too complicated words.
In the traditional swimming pool, the water is sucked in by the pump through openings called skimmers; it is then filtered and pumped directly into the pool – it is a closed circuit. The only loss of water, apart from the washing of the filter, is due to evaporation in the pool, mainly in summer. The water level is about 15 cm below the coping stones.
In the negative edge pool or the zero edge pool , the water is not sucked into the pool, but into a so-called “balancing” tank; after filtration, the water is returned to the pool by means of outlets (generally in the walls and at the bottom) and can only overflow since the pool is already full! The water flows into a gutter where it is collected and then redirected by gravity into the balancing tank.
As for the skimmers, we are in the presence of a closed circuit: it is the same water that circulates, so no special anxiety for water consumption. Here the water line is 3 to 4 cm under the coping or even at the same level for the zero edge pool.
They are essential to a infinity pool construction and are not necessarily expensive.
The balancing tank is of course essential for the operation, since it is from there that the water will be sucked by the pump to make the pool overflowing. There is a lot to be read about the calculation of its volume; normally not only the volume of the pool, but also the pump flow rate calculated on the basis of the length of the overflow and the number of bathers to be expected, must be taken into account. Too small will be insufficient in case of rainwater or overuse of the pool, and water will be wasted; too large is money wasted on masonry and chemicals.
The function of the gutter is to collect the water that overflows from the pool and fill the tank. Its location depends on the type of overflow; on a waterfall pool, it is located below the side(s) through which the water overflows. In a zero deck level pool, it will be located around the entire perimeter of the pool.
The bottom inlets nozzles (not to be confused with the bottom drain) are often forgotten but they are essential in the technique of reverse hydraulic.
The balancing tank level control system is also very important. Its role is to make your life easier and to avoid important water losses or big problems at the pump. More or less economical solutions exist: floats, probes, bubbler. The no-return or check valve and a solenoid valve to fill automatically the tank are also necessary. See our post about balancing tank level control.
Let’s explainl what is true and what is rumour about the technique of the infinity pool.
The balancing tank must be at least 10% of the pool volume: this is FALSE. It is much less. The calculation must take into account the volume of the pool but also the flow rate of the filtration pump related to the length of the overflow.
A second pump is necessary: this is FALSE. If the masonry has been properly executed, this pump is totally useless. However, this is only true for a small pool with a long overflow length, for instance a mirror pool, or when you want to increase the water level of the overflow to hide a defect in the level of the overflow.
The filtration must be oversized: this is FALSE. For the same reasons as above.
A special disinfection system is mandatory. NO! We obviously advise our customers to equip their pool with an automated treatment, but an overflow pool can be treated like a skimmer pool. The proof: infinity pools existed long time before salt disinfection or other automatic systems were available on the market!
It is impossible to install an immersed cover on an overflow pool: this is obviously FALSE. Otherwise nobody would want to build one anymore. There are many suppliers on the market, but many of our customers have been satisfied with AZENKO.
It is impossible to transform a skimmer pool into a cascade overflow pool: Again this is FALSE. You will find an example in this post.
The price of an infinity pool is higher than that of a skimmer pool: it is TRUE! You have to count between 20 and 25% more. But by building it yourself or with non-specialized craftsmen you can save up to 30%. I’ll let you do the calculation. We will help you in this process.
The advantages of an infinity pool
They are of two kinds: technical and aesthetic
The main technical advantage is a cleaner water. Indeed, the water is perfectly recyclable over its entire surface, where the pollution is the strongest: surrounding dust, solar oil, pollens, …! In addition, the bottom inlets allow impurities to rise to the surface. Main consequences: fewer dead water zones and better efficiency of the treatment products. It is not for nothing that public swimming pools have been overflowing for a long time!
Just look at the pictures of overflowing pools to understand the visual effect and aesthetic interest. A cascading infinity pool built on a sloping plot opens up the horizon, but you don’t need a panoramic view! A zero edge pool with the water level at the same level as the coping stones brings a feeling of zenitude to a garden, even if it is small.
Studies prove that a swimming pool adds between 5 and 20% to the value of a house. It goes without saying that an infinity pool will bring even more.
How to reduce the cost of an infinity pool ?
Although an infinity pool is technical, it can be built by companies that do not specialise in swimming pools. This way you can make your dream come true without breaking the bank.
We can help you in your infinity pool construction in these ways:
- We will create a unique design for you that matches your property and your wishes.
- We design precise plans of structural and hydraulic details so that masonry and plumbing companies can carry out the work.
- We help you by following remotely the construction site from the start of your pool till commissioning.
Perhaps would you like to know more about us before contacting us !