Both saltwater and chlorine systems are used to clean spas and swimming pools. Chlorine is a powerful chemical that will kill any pathogen it comes in contact with, even at trace amounts, making it an ideal choice for keeping pools clean and safe to use. Both salt and chlorine systems require that you check the pH balance of the water regularly to ensure that it is alkaline enough to prevent most microorganisms from surviving inside. If it becomes too acidic, it can burn a swimmer's eyes and possibly even damage skin. Since salt systems use chlorine as well, these pools will also need to be checked.
There are two ways to add pure chlorine to a pool. The first and most simple way is through additives such as chlorine pills or packets that add in a mixture of chemicals to the water. These chemicals run through the filters and are circulated throughout the water, keeping it clean. The second method, sometimes reserved for larger and more expensive pools, uses a chlorinator, or a device that keeps a small tank of pure chlorine and injects a certain amount into the water as it passes through the pool filter. This automatic process can keep track of how much chlorine is in the water, making it easier to maintain than chlorine additives, which require frequent testing.
Salt water pools also use a chlorinator, but a different version that includes an electrolysis device that extracts chlorine gas from salt. This gas is mixed with a small amount of pool water and then sent back into the pool, where it does its job and then slowly dissipates. Only salt needs to be purchased with a salt chlorinator, since the devices creates its own chlorine.
Many people with sensitive skin or those who dislike the smell and roughness of chlorine prefer salt chlorinators. Because the salt versions inject a constant stream of chlorine into the pool, the waves of chlorine sent by other filters are not needed, and the most noticeable effect is a slight salty taste and feel to the water, about one-twelfth of the salt found in the average ocean. On the other hand, salt chlorinators cost more money to purchase and set up initially, and are available from fewer distributors. Traditional chlorinators, on the other hand, cost less and readily available, with a multitude of chemical brands to choose from.
While salt chlorinators do not release as much chlorine into pools and are easier to regulate, they do come with added costs. Salt is corrosive, and wears through filter parts and pipes more quickly than traditionally chlorinated water, requiring more frequent replacements and repairs to pool systems.
The most popular alternative to both salt and chlorine systems is the ozonator. These devices, which are similar to those used in water purification plants, release a stream of ozone gas into the pool water. This gas, which is ionized oxygen, oxidizes any particles it comes in contact with, and destroys pathogens and odors. The main byproduct is oxygen and the water remains pure and uncorrosive. Ozonators require a complex system to work effectively and are much more expensive to install than other options.