Types of Water Filtration Systems for a swimming pool in the UK

Traditional, Monobloc and Infinity Pool Weir Systems

The 3 Basic types of Pool Water Filtration System


There are three different types of pool water filtration systems

Traditional filtration

With traditional filtration the pump and the filter are kept separate from the basin or pool structure and are connected to it by a network of pipes.

The pool plant room that houses the pump and filter should be weatherproof and not more than 15 m from the swimming pool, nor closer than 2 m from it.

The head loss in the system that the pump must overcome normally varies between 0 .5 and 1.0 bar in most domestic systems - this is equivalent to a head of water between 5 and 10 m.

The pump must not be installed more than 1 m above the pool water level for the purposes of water aeration and an anti-siphon device may be required. If the pump and filter are below the level of the water in the swimming pool a non-return valve will be required in the line between the pool main drain and the filter.

A manometer or or pressure gauge must be positioned between the pump and filter so that as the filter gets dirtier, and the pressure resistance in the filter increases, it can be seen a pressure increase on the manometer.

The water is aerated as it leaves a swimming pool via the skimmers, before being pumped through the filter and returned to the pool.

A main drain at the deepest point the pool must also be provided to allow the proportion of the circulation to move through it.it is.

In order to stop the pump and filter from being damaged by ice in the winter the pipework needs to be easily demountable with manually operated unions and sufficient valves must be provided to allow the pump and filter to be de-watered and to allow all the following circuits to be operated independently:-

Integrated MonoBlock Filtration System

These can be in the pool wall, an over the wall system or are somtimes installed alongside the Roman steps.

They are not normally installed on swimming pools that were longer than 10 m. Because they rely on a giratory system of water circulation they are more suited to oval or round pools or even rectangular pools with angled corners.

The filters are normally cartridge filters that will need to be renewed a couple of times a year.

They provide a large economy in the pool initial cost but will probably not produce safe healthy water during prolonged hot weather periods in July and August.

Filtration across a Weir

This type of system will normally be seen in a public pool with a water area greater than 200 m² or in a private " Infinity swimming pool" or in a private indoor swimming pool where they are known as "Deck Drains"

These result in quite complex hydraulics, piping systems, pumps and filters that are beyond the scope of this article.

If the infinity edge is 5 m long the maximum depth of water over the weir that forms the infinity edge would normally be about 5 mm.