Salt water chlorinators make chlorine from salt. They come in two parts - a set of electrodes and a control panel. The electrodes are typicaly small metal plates very close together that have an electrical charge sent through them. The charged plates essentially strip the chlorine atom out of the salt to make it in to the type of chlorine that can kill bacteria and algae. Once the bacteria have been killed the chlorine is released back to the water and the elecrodes re-form it again and again giving you a constant supply of chlorine. With a salt water chlorinator installed you will never need to buy chlorine again.
The set of elecrodes is called the "cell". The cell has to be installed somewhere on the pipework on the return flow to the pool. The best time to do this is in the construction phase of the pool but the salt water cell can be retro-fitted, some are easier to retro fit than others.
Having installed the cell on the pipework it is connected to the conrol panel that is usually fixed to the wall in the pool room. How much chlorine the cell produces is set by the control panel which will also tell you if your salt concentration in the pool water is correct.
Before using a salt water chlorinator you have to have salt water. The typical salt concentration for most chlorinators to work is 4 grams of salt for every litre of water or 4,000 parts per million (ppm). For anyone used to dealing with chlorine at levels of 1ppm you will soon realise this is a lot of salt. For a typical 12 x 24 pool with 30m3 of water that is 120kg. Salt usually comes in 25kg bags so that is 5 bags. The cost per 25kg bag is about £10.00 but you only have to put salt in once.
For more on how salt chlorinators work have a read of our blog posting.