About Sanitisers (Chlorine)
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Chlorine is the common sanitiser for your pool. Bacteria can grow in any untreated body of water with swimmers being the primary source of contaminants along with rainwater, leaves, grass, dust, and pets.
Having a sanitiser in the pool water at recommended levels will eliminate most of the bacteria in the water by basically tearing apart a germ, shredding its cell membrane and proteins.
The neutralised bacteria is then filtered out and any residual sanitiser left in the pool water will prevent any new bacteria growth.
The recommended Chlorine level in a standard outdoor pool is between 2.5 - 3.0ppm (parts per million)
Heated pools and spas require a higher level of sanitiser than non-heated pools. This is because sanitisers are consumed more quickly in hot water.
*The majority of the information in this article is for swimming pools. For more information on sanitiser options for a stand-alone spa, please contact us in-store or via the button below.
Types of Sanitisers
Each form of chlorine and its production has its own individual features, pros, and cons.
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 and 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.
COMMON MISCONCEPTIONS - 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.
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.
Learn more about these very low chlorine system options and contact us to find out which is right for your pool! Mineral Swim system from Maytronics or Magnapool by Zodiac and Naked Pools Fresh Water System
COMMON MISCONCEPTIONS - 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 a simple as super chlorination or use of a non-chlorine Oxidiser like Oxyshock, however, it’s always best to have your water tested first, come in and see one of our staff with a water sample.
