Swimming pool filter – different options

Most outdoor swimming pools need a heater, a pump and most importantly a filter to keep the water clean and safe. If you have an outdoor pool with all three of these accessories you will be able to get the maximum use from your pool with the smallest amount of disruption from poor weather and cleaning tasks.

The job of a filter is to remove any dirt or debris from within pool water and, along with the pump, it will play a part in distributing friendly chemicals throughout the water.

What does the filter do

The filter and the swimming pool pump work together as a double act. The pump circulates the water and pushes (or sucks) it through the filter and its filtration system. This allows the filter to “filter out” any particles and impurities.

All filters use some form of filtration chamber that filters out these tiny particles of debris. However, there are three very different ways of doing this by using sand, a filter cartridge or Diatomaceous Earth (DE). Whichever filter type is used the objective remains the same – to keep the pool water healthy and clean.

Filtration systems

There are 3 different types of filtration system for a swimming pool and each system has its own advantages and limitations. The options are –

• Sand filter
• Cartridge filter
• Diatomaceous Earth (DE) filter

The main factor that discriminates between each of these filtration methods is the minimum size of particle that they can filter.

The other factors are the initial cost and set-up and the replacement and maintenance costs for each system. Which system is best will depend on the size, usage and situation of the pool in question.

Different filters

Here is a summary of each of the three main filtration systems.

Sand filter

Sand based filters are the most popular outdoor swimming pool filtration method. They use sand in the form of a filtration bed.

A sand filter is the cheapest type of filter to buy and operate and it is efficient and cheap to run. On the downside, it does require more space than the cartridge filter and it does not remove very small particles as well as the other two systems.

The only real problem with the sand based filter is that it has a tendency to clog-up from time to time, however this can be resolved without great expense or time.

Cartridge filter

This system uses a removable cartridge and, although the cartridges require frequent replacement, they require no specialist skills and this makes them easy to maintain.

Another advantage includes the ability of the cartridge to remove very small particles and, in this respect, they are superior to sand based systems. The drawback to the cartridge filter is that it will only work on small to medium sized pools and the cartridges are expensive to replace.

Diatomaceous Earth (DE) filter

This is the least popular, most complex and probably most expensive swimming pool filter alternative. It does however offer the best performance and it can remove the smallest of particles (i.e. 3 microns in size). For this reason it is often the choice for large and heavily used pools where the filter does a lot of work and where cost is not a restrictive factor.