Osmosis in Swimming Pools: What It Is and What It’s Used For

Osmosis in swimming pools can refer to two different concepts. On the one hand, reverse osmosis is a system that treats water and reduces the presence of salts and other dissolved substances. On the other hand, in a fiberglass pool, osmosis describes a deterioration of the liner that can cause small blisters or bulges.

It’s important to distinguish between these two concepts, especially in commercial pools, where water quality and the condition of the materials directly affect the maintenance of the facility.

Reverse osmosis: What is it?

If you’re wondering what reverse osmosis is, it’s a water treatment process based on the use of membranes.

Simply put, water is forced under pressure through a membrane that allows water molecules to pass through while retaining some of the salts and other dissolved substances.

The result is water with a lower concentration of certain compounds.

This technology has been used for years in water treatment and desalination processes and can also be applied in aquatic facilities when the characteristics of the source water require it.

What is reverse osmosis used for in a swimming pool?

Standard pool filtration primarily removes particles and debris from the water, but it does not treat salts and dissolved substances in the same way.

Reverse osmosis can be useful when the water used to fill or top off a pool contains a high concentration of these substances.

For example, it may be beneficial in facilities where:

• The available water has high salinity.
• Brackish water is used as the water source.
• The water must be pretreated before being introduced into the system.
• The water’s composition makes it difficult to maintain appropriate parameters.

This does not mean that all swimming pools require reverse osmosis. Its use depends on the specific characteristics of each facility and, above all, on the quality of the available water.

Furthermore, reverse osmosis does not replace other essential processes. A swimming pool still requires an adequate system for filtration, recirculation, disinfection, and water quality control.

What is the relationship between reverse osmosis and water quality?

Reverse osmosis reduces the concentration of certain substances, but pool water must maintain a proper balance.

One of the parameters that should be monitored is hardness, which is primarily related to the amount of calcium and magnesium present in the water.

Excessively high hardness can promote the formation of deposits and scale. Conversely, a level that is too low can also affect the water’s balance.

That is why it is important to know the hardness of pool water and analyze it along with other parameters such as pH or the disinfection system.

In other words, using reverse osmosis isn’t simply about removing salts. The goal is to achieve water that’s suitable for the pool’s characteristics and then maintain that balance through proper treatment.

Osmosis in fiberglass pools: What does it mean?

The search term “osmosis in fiberglass pools” refers to an entirely different problem.

In certain pools made of fiberglass-reinforced polyester, small blisters or bulges may appear under the liner. This phenomenon is commonly known as osmosis.

It should not, therefore, be confused with reverse osmosis treatment:

• Reverse osmosis: treats water using membranes.
• Osmosis in fiberglass pools: affects the pool’s liner.

Signs can range from small surface irregularities to more visible areas on the finish.

When these types of symptoms appear, it is advisable to inspect the condition of the surface and determine the extent of the problem before performing any repairs. A proper diagnosis will determine whether it is actually osmosis or another form of liner deterioration.

How to Replace Reverse Osmosis Filters

Another common question is how to replace reverse osmosis filters.

These systems typically include pre-filters designed to protect the membranes and prevent certain particles from reaching them. Over time, the filters lose their effectiveness and need to be inspected or replaced.

The process varies by system, though it generally involves:

1. Shutting down the system.
2. Shut off the water supply.
3. Relieving the pressure according to the manufacturer’s instructions.
4. Removing the used filter.
5. Install the new filter in the correct position.
6. Check the connections and seals.
7. Restart the equipment and check for leaks.

The replacement frequency varies by installation. It depends on water quality, system usage, and the characteristics of the filters.

Therefore, for commercial pools, it is important to follow the manufacturer’s specific maintenance instructions rather than setting a generic schedule.

When is it worth using reverse osmosis in a pool?

Reverse osmosis may be a good option when there is a specific need related to the quality of the incoming water.

Before installing such a system, it is advisable to analyze what substances the water contains, what treatment the pool actually needs, and how the reverse osmosis system will integrate with the rest of the equipment.

It is also important to consider maintenance, the energy consumption associated with the process, and the wastewater generated by the system.

In a commercial pool, efficiency does not depend on a single technology, but rather on filtration, treatment, recirculation, and chemical control working in coordination.

In short, reverse osmosis in swimming pools is a solution for treating water when its composition makes it necessary, whereas osmosis in fiberglass pools is a problem related to the lining. Correctly identifying which type of osmosis we’re dealing with is the first step toward applying the appropriate solution. At Fluidra, we take a comprehensive approach to water treatment, combining different technologies to create commercial pools that are more efficient, sustainable, and easier to maintain.