For over one hundred years the wet leisure and spa industry has been looking for new ways to keep the water clean, clear, safe, and enjoyable for the bather. Over this period technology has come along way and now we have systems that are more environmentally friendly and safe such as chemical free swimming pools.
On todays market there are around five main swimming pool sanitisers and one new one which is at the end of the blog. The main ones are Chlorine, Ozone,UV, Saltwater and Hydroxyl injection.
- Chlorine: At the beginning of the 20th-century technicians found a way to disinfect water with new chemical chlorine and it rapidly became the first chemical used in the swimming pool industry. In the USA, the Brown University in Rhode Island started using chlorine to sanitize its swimming pool and is known in the pool industry mainly in the United States as the first university to use chlorine sanitation.
- Ozone: The year is 1906 and the French started to use Ozone as a method of purifying drinking water. By 1961 in Europe this method was widely used in most countries. Then in 1977, there was an estimated number of 1039 Ozone sanitization plants located around Europe. Finally, the United States decided to adopt this now proven swimming pool treatment technology and launched it in 1975.
- UV: This stands for ultraviolet light. This was discovered by scientists in the 1920’s and again is old technology alongside Chlorine and Ozone. The UV lamps come in contact with the water and it attacks the algae and the bacteria in the swimming pool. By the 1970s this UV technology was becoming the preferred method of water sanitization in the process plants for drinking water and wastewater. In the last ten years, this system has gone out of favor due to its high running costs and other more effective sanitization systems
- Saltwater: In the 1960s an Australian pool engineer discovered using salt was a cheap way of producing chlorine to keep the water clean to swim in. Saltwater chlorinators are responsible for 80% of the Australian swimming pool market but recently the percentage has reduced due to other new healthier systems. In the 1980s began to use these saltwater systems and now have replaced the majority of chlorine-based pools.
- Direct Hydroxyl Injection: In recent years the trend has been to move away from unhealthy and environmentally sanitization systems. Treating oxygen in the air around the sanitizer to create monatomic oxygen was first introduced in the early 2000s and by 2014 it started to be used in swimming pool sanitization. This technology is a good secondary sanitizer as it only destroys bacteria in the swimming pool water.
Using Oxidisation, Ionisation and descaling is now the most modern system that renders all the above now outdated. This technology is available from our website. The next part of this blog to explain how the filtration system work.
HOW DOES A SWIMMING POOL WATER FILTER SYSTEM ACTUALLY WORK?
Your pool pump sucks the pool water from the skimmer or skimmers located around the circumference of the pool lining, pool wall, and the main drain or drains on the bottom of your pool.
The system work when the water flows through the pump to the pool filter which removes the dirt and any debris and bacteria if you have a high specification pool filter. Then the water flows through the pipework and plumbing to a water heater if you have one, then through your water sanitizer. The sanitizers come in all shapes and forms from Quest ionizers and oxidizers to simple UV or saltwater chlorinators.
The clean water is then sent back into your pool by the means of pool jets located around the pool.
What is a skimmer and drain?

You should already know what these are but if you are new to the swimming pool industry here is a very basic overview.
The skimmer is normally a square or rectangular hole located at the top of the swimming pool wall. The opening area will normally be about halfway above the skimmer to flow down it freely. The swimming pool drain is just like the one in your bathtub, keep the plug on it! ( Some pools that are installed nowadays don’t have main drains as the skimmers do the job quite adequately ). The water then flows into the main pipework down towards the pump and filter for the water to be cleaned.
The Swimming Pool Pump
The pool pump nowadays comes in all sorts of shapes and sizes, but the main style is that the pump motor is normally located at the rear of the pump and the round STRAINER pot is located at the front with an inspection lid.

Inside the pump is a spinning impeller which is the part that spins at high speed and pulls the water in from the swimming pool. The water flows in through the strainer pot which will catch most of the debris from the pool water. It then gets sucked from the strainer pot into the filter.
Swimming Pool Filter
With developments over the years in the swimming pool filter technology, you now have different options depending on the type of pool and sanitization system you use.
- Cartridge Filter Systems
- Sand Filter Systems
- DE Filter Systems
- Glass Filtration Systems
CARTRIDGE FILTER
A cartridge filter is a filter that does what it
Say uses cartridges that are made from large sheets of polyester material folded into the shape of the chamber of the cartridge. You can buy single cartridge filters or dual or multiple filters depending on the size of the pool and sanitization system you are using.

Sand Filter
Next, we have the sand filter. This is a filter that uses sand rather than cartridges. The tank is normally half full of sand and has pipes plumbed in on the side of the tank and at the bottom which allows the water to flow through the sand and is subsequently cleaned.
DE filters stand for (Diatomaceous earth ). This system has a filter cloth inside a chamber that has grids or lanionscoated in a D.E. The compound DE comes from sedimentary rock. The water flows through the chamber and is filtered in a more concentrated way than other filter techniques.

Glass Filtration Systems
Glass filtration systems are becoming more popular due to media and more people preferring the sound of using glass instead of sand in a filtration system. It will last much longer than using sand in a filtration system. However, the glass will still need to be replaced every five years or so. It does have another advantage of using approx 50% less water when you are backwashing.
What is Backwashing Or Backwash?
Backwash or backwashing is a method to intensely clean your swimming pools filtration system and to try and avoid you manually cleaning. It won’t take long to backwash usually only a few minutes or so.
To carry out backwashing your swimming pool you need to reverse flow the water through your filtration system. The process may sound like it could damage your filtration system , but don’t worry today most filtration systems are designed for backwashing.
The process of backwashing dislodges any debris , phosphates , contaminants etc. You are simply flushing them out through your valves waste line or hose that you connect to your hose pipe.
How often should you backwash your pool?
The frequency of backwashing your swimming pool depends on how much you actually use your pool, what sort of pool sanitization system you have, what sort of filtration system, and also where your pool is located.
If your pool is located outside its more likely to have more dirt and debris in it compared to an enclosed pool. For example, twigs, animal droppings organic debris etc.
Rule of thumb is that you should be looking at backwashing your pool about once a week or in a scheduled programme given to your pool maintenance person or yourself. Another way of noticing if you need to backwash your filtration system is that if the filter pressure gauge has dropped. If it drops to around 8 to 10 PSI over the start level or clean pressure carry out a backwash. Also check your regular running pressure and if it has increase again carry out a backwash sequence.
One last note if your swimming pool is located outside and you do have a nice garden or yard with trees and plants it is always a good idea to invest into a pool vacuum cleaner. This will remove the larger debris before it goes into your filtration system and save your filtration that extra work.
My last point to make is that when you are backwashing you will lose some swimming pool water which is unavoidable, try not to overdo it. Keep an eye on the color of the water that is going back into the pool through the pump inspection glass. Once its crystal clears it’s time to stop the process.
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