Bromine tablets are widely used to sanitise spa baths and also indoor swimming pools. The features, benefits and disadvantages are described below.
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Buy bromine tablets
- Bromine tablet - Benefits
- Bromine tablet - Disadvantages
- Shock dosing
- More information about swimming pool and spa water treatment
Bromine tablets contain 63% bromine.
Most commonly supplied as an 18 to 20gm tablet.
1.6 gm dissolved from a bromine tablet will raise the free bromine level of 1,000 lt water by 1 mg/litre (part per million).
The tablet is approximately 3cm diameter and 2cm high.
Calculate the bromine tablet dose rate for a known water volume
Regulatory Information Use this to check what is behind the brand name. Often you are buying a simple chemical. Look on the regulatory part of the label and most of the following should be there.
- Chemical Name (or "contains"): 1-bromo-3-chloro-5,5-dimethylhydantoin or bromochloro-5,-5 dimethylhydantoin
- UN 1479 Oxidising Solid, Not Otherwise Specified (shortened to NOS)
- CAS No. 32718-18-6 (Not obligatory in the UK)
For full information, download a safety data sheet
Free bromine is tested with DPD1 tablets, Total bromine is tested with DPD3 tablets. The combined bromine value is obtained by subtracting the free bromine value from the total bromine value.
More information about DPD Tablets
With most people, bromamines are much less likely to irritate. Because of this bromine tablets are often more suitable for use in the higher temperatures of spa baths.
Because they do not contain calcium, bromine tablets can be used to sanitise hard water without increasing the calcium hardness.
As they are in a tablet form, BCDMH is suitable for semiautomatic dispensing using an erosion feeder or brominator.
When shocked with an Oxygen Shock, the bromide ions are reactivated as the bromamines are destroyed.
Bromine tablets have little effect on pH
Monobromamine, unlike monochloramine does have a reasonable sanitising value
Bromine tablets cannot be stabilised in the same manner as chlorine. This makes bromine sanitised water very susceptible to degradation by ultraviolet light.
Roughly twice the quantity of bromine is needed to achieve similar sanitising levels to chlorine.
A very few people are susceptible to skin irritaion which may be associated with sanitising with 1-bromo-3-chloro-5,5-dimethylhydantoin. This may be attributable to dibromamine or tribromamine formation, indicating insufficient attention to shock treatment
"Bromine" is a little more expensive than "chlorine" generally.
Bromine tablet disadvantages
Bromine is only a weak oxidising agent, not capable of destroying amine contamination in a pool or spa. Because of this a regular separate shock treatment is necessary .Shock dosing
Shock dosing is a process by which bather impurities are removed from the pool water. When bromine combines with amines it forms bromamines. The first stage of bromamine formation is monobromamine which has reasonable sanitising value. Usually oxygen compounds called Oxygen Shock or Non Chlorine Shock are used for shocking bromine treated water.
