Your choice of filter should be based around:
Sand filters are equipped with a tank filled with sand grains that clean the pool water. They filter out debris down to sizes of approximately 50 μm. This is the most common type of filters and suit all pool basins. However, it requires backwashing and therefore involves releasing water into the wastewater system.
Cartridge filters are suitable for all types of pool. They filter out debris down to sizes of approximately 20 to 25 μm. These models are simple to install and maintain, and are perfect for small plant rooms. In addition, they don't require backwashing and can help save up to 6000L of water per year!
Diatomaceous filters are considered to have the best performance with a filtration size of 5μm, and produce crystal-clear water. In order for them to operate correctly, regular cleaning is needed (every 3 to 5 weeks). However, they require backwashing every 2 months to eliminate built-up dirt. The diatomaceous earth released during backwashing must be collected to prevent it from entering the wasterwater system, and the level of diatomaceous earth in the pool must then be partially replenished.