We have been working for years with differentnatural purification systems for swimming pools, and one of the most talked about elements is the ultraviolet filter.
Despite its name, technically it is not a filter as such, but a biocide system that uses ultraviolet (UV) radiation to eliminate microorganisms such as bacteria and algae present in the pool water.
How UV radiation works in pool treatment
The process is quite simple: the pool water passes through a tube containing a UV lamp. This lamp emits ultraviolet radiation, which is lethal to pathogenic organisms such as Escherichia coli bacteria or single-celled algae.
Differences between a UV filter and other purification systems
It is important to note that the UV filter does not completely replace other purification systems. It works as a complement to these, helping to remove micro-organisms without introducing additional chemicals into the water, but as it is responsible for killing micro-organisms we do not consider it suitable for natural pools.
Benefits of UV filters in pool maintenance
One of the main benefits of a UV filter is that it removes bacteria and algae without the addition of chlorine or chemicals.
This makes it a more ‘green and environmentally friendly’ solution, especially for pools looking to reduce their environmental impact, but natural pools are all about encouraging biodiversity and the momentary solution can throw the system out of balance.
Bacteria and algae removal without chemicals
Some of our customers encounter recurring problems with bacteria or algae in the pool water, even when using traditional chlorine systems. In these cases, the UV filter is very effective in removing unicellular algae and improving water quality, as these organisms are particularly vulnerable to UV radiation.
Improved water transparency in pools with excess nutrients
There are situations where, due to high concentrations of nutrients such as phosphates and nitrates in the water, the pool can become cloudy.
We have seen that, despite adding plenty of chlorine, algae and bacteria still find nutrients to survive.
In these cases, the transparency of the water improves significantly when a UV filter is used, as the micro-organisms that contribute to turbidity are removed.
Reduced use of chlorine and chemicals
By incorporating a UV filter into the purification system, the amount of chlorine or other chemicals normally used in pool maintenance can be significantly reduced, which is also a benefit to bathers who will experience softer, more natural water.
Limitations and considerations of UV filters
While UV filters are a powerful tool, they are not a magic solution to all problems.
They do not remove algae that cling to the pool walls, as their range of action is limited to the water passing through the system.
Why UV filters do not remove algae on the walls
In our experience, we have observed that when the pool water has an excess of nutrients, the UV filter can remove the unicellular algae floating in the water, but it can do nothing against the algae that are already attached to the walls.
In fact, in some situations, the algae on the walls can take advantage of the nutrients released by the algae removed by the filter, which encourages their growth.
Cases in which a UV filter is not enough to maintain the pool
If the pool has serious nutrient or algae problems, the UV filter alone will not be sufficient.
In these cases, it is essential to combine the UV filter with other purification methods or even reconsider the biological balance of the pool.
UV filters in natural pools and ponds
UV technology has also been used in natural ponds and pools, although its application here is more limited.
Are UV filters suitable for natural pools?
In natural pools, where biological balance is essential, the use of a UV filter may be counterproductive in the long term.
Although in a natural pond or pool we may have occasional transparency problems, the UV filter kills both algae and phytoplankton, organisms essential to the ecosystem.
How UV filters affect the ecosystem of a natural pool
If used continuously, UV filters can kill these micro-organisms, which eventually causes the algae on the walls to absorb nutrients and proliferate further.
In our natural pools, we focus on biological solutions such as plant filters to manage the nutrient balance.
Spot use of UV filters after rainfall and nutrient inputs
A strategic use of the UV filter can be beneficial after one-off events, such as a mud shower or a build-up of leaves, where nutrients in the water are temporarily increased. In these cases, turning on the UV filter for a short period can quickly restore transparency.
When to use a UV pool filter?
The UV filter can be useful in situations where the pool has recurring transparency problems or when there are unexpected events that alter the water quality.
Pools with recurring transparency problems
When, despite the use of chlorine or other purification systems, the pool still has a greenish or cloudy appearance, the UV filter can be a complementary solution to eliminate the algae and bacteria responsible.
Occasional events where a UV filter can be the ideal solution
As mentioned above, situations such as a mud shower or unexpected nutrient input can cause the pool to be temporarily affected. In these cases, the UV filter acts quickly, removing the responsible particles and restoring clarity to the water in a short time.
Comparison of UV filters with other purification systems
When comparing the UV filter with other methods, such as salt chlorination or ozone systems, there are several advantages and disadvantages.
Advantages and disadvantages of UV filter versus salt chlorination
Salt chlorination is still one of the most common methods of disinfecting pools, but the UV filter offers the advantage of being a chemical-free solution, which reduces skin and eye irritation, something that many appreciate.
How does the UV filter compare with ionisation and ozone systems?
Ionisation and ozone systems are also popular for their ability to reduce the use of chemicals. However, the UV filter has the advantage of removing pathogens instantly, whereas the other systems require more time to work.
Maintenance and care of a UV filter
Maintenance of a UV filter is relatively simple, but it is important to change the UV lamp according to the manufacturer’s recommendations to ensure its effectiveness.
UV lamp life and replacement
Most UV lamps have a service life of approximately one year. After this time, even if the lamp continues to function, its ability to emit sufficient radiation to kill pathogens diminishes and it needs to be replaced.
Tips for keeping the filter in optimal condition
We recommend regularly inspecting the quartz tube that protects the lamp, as any dirt or build-up on the glass can reduce the filter’s effectiveness. Keeping this component clean is essential for the correct functioning of the system.
Is the ultraviolet filter the ideal solution for my pool?
Conventional pools vs natural pools: Where to use a UV filter?
In conventional pools, the UV filter is an excellent complement to improve water quality and reduce the use of chemicals. However, in natural swimming pools, its use must be targeted and strategic, so as not to interfere with the balance of the ecosystem.
