Bacteria can grow in any untreated body of water with swimmers being the primary source of contaminates along with rainwater, leaves, grass, dust and pets.
Having a sanitiser in your pool or spa at recommended levels will eliminate most of the bacteria in the water. The neutralised bacteria is then filtered out & any residual sanitiser left in the water will continue to work to prevent new bacteria growth.
SANITISER = CHLORINE
The recommended Chlorine level in a standard outdoor pool is between 2.5 - 3.0ppm (parts per million) with heated pools and spas requiring a higher level of sanitiser than non-heated pools. This is because sanitisers are consumed more quickly in hot water.
*Please note: The majority of the information in this article is for swimming pools. For more information on sanitising your spa, please click below.
Types of Sanitisers
Each form of chlorine and its production has their own individual features, pros and cons. Our knowledgeable staff can happily help you work out which form of sanitation is best for your pool/spa and lifestyle.
LIQUID CHLORINE
(Sodium Hypochlorite)
It is most commonly available as a liquid. Liquid chlorine is the most economical and can be dosed automatically, however, the storage containers are bulky and liquid chlorine has a limited shelf life due to loss of strength over time from heat and sunlight. It also has a naturally high pH level at 13 which will always increase the pH of a pool or spa, requiring it to be rebalanced after each dose.
GRANULAR CHLORINE
Granular chlorine is a more convenient option compared with liquid chlorine as it's more concentrated and easier to store. However, it’s more expensive and cannot be dosed using an automatic feeder unless it is in tablet form via a float and comes in 2 common forms, Calcium Hypochlorite and Sodium Dichloroisocyanurate.
Calcium Hypochlorite - Available in granular or tablet form, has between 60-70% available chlorine (effective chlorine content). As it is made up of Calcium, continual use will increase your Calcium Hardness levels over time which can affect your pool surface. The ideal Calcium Hardness levels for concrete and pebble surfaces is between 200-400, Fibreglass between 120-250 and Vinyl liners 20-150. If these levels become too high, scale formation on the pool surface is possible.
*As a guide, for every 1ppm increase in your chlorine level, you'll get about a 0.7ppm increase in your Calcium Hardness level.
Sodium Dichloroisocyanurate - Also available in granular or tablet form, is usually about 50-60% available chlorine. This form of chlorine also contains Cyanuric Acid or 'stabiliser'. Continual use of Sodium Dichloroisocyanurate will continually increase your level of Cyanuric Acid and these can potentially get too high and cause a 'chlorine block' whereby it inhibits the ability for your chlorine to work effectively.
*As a guide, for every 1ppm increase in your chlorine level, you'll get about a 0.9ppm increase in your stabiliser level. For an uncovered, salt or chlorine pool, the ideal Cyanuric acid level is between 40-60.
Types of chlorine production
AUTOMATIC CHLORINATORS
Chlorine can also be generated by salt or mineral chlorinators. Chlorinators use a process called electrolysis. In a saltwater chlorinator, it works by using an electrical charge to 'split' the Sodium Chloride (Salt) into Sodium and Chlorine. It is circulated into the pool so it can kill bacteria and viruses and prevent algae growth around the pool.
Eventually, this natural form of chlorine is used up and reverts back to the original two elements of sodium and chlorine = salt.
LOW CHLORINE SYSTEMS
These systems are fast becoming very popular. They’re a much healthier alternative to manually adding chlorine or using a saltwater chlorinator. It’s great for people who have an intolerance to chlorine or who live with conditions such as asthma or eczema.
These are sanitising systems that produce only a very small amount of chlorine and use other techniques such as Ioniser or Ozone systems to keep the pool clean, clear & healthy.
These systems require a much lower level of chlorine as a primary sanitiser, as they also use either an Ionising rod or an Ozone generator to produce a secondary sanitiser which is often much more effective than chlorine & creates a "fresher" or more natural feeling water.
Click below to learn about the Mineral Swim System or contact us to find out which low chlorine system would be right for your pool.
Common Misconception #1
Chlorine Odour
A strong chlorine smell doesn’t always mean too much chlorine, it could mean too little. The odour is produced by chloramines and these can also cause sore eyes and itchy skin.
To remove chloramines, it can be as simple as super chlorination or the use of a non-chlorine Oxidiser like Oxysheen for pools and Purity for Spas, however, it’s always best to have your water tested first, come in and see one of our staff with a water sample
Common Misconception #2
SALT IS USED UP IN CHLORINE PRODUCTION
Salt chlorinators do not use up the salt to create chlorine. Saltwater chlorination is a closed-loop system, the salt isn’t used up in the process as it reverts back to Sodium Chloride (Salt) and repeats the process all over again.