The right balance of chemicals is essential for the sanitisation and maintenance of a clear, healthy swimming pool or hot tub.

While my previous article titled ‘Crucial Chemical Maintenance for a Healthy Swimming Pool’ outlined the key factors involved in administering pool chemicals, this guide will compare the two main types of chemicals used for sanitisation – chlorine and bromine – so you can better decide which one will suit your needs.

Key Facts About Chlorine

Generally speaking, the use of chlorine is the simplest and most common method of sanitising your pool or hot tub by killing bacteria and controlling the growth of algae.

This chemical is fairly easy to use with a pH balancing test kit, which measures the acid and alkalinity levels of the water. It must also be administered every now and then in high doses as a shock treatment, especially when the pool or hot tub has not been in use for awhile. See the below paragraph for further info on shock treatments.

These days there is a variety of chlorine products available on the marketplace. All however require a pH level between 7.4 and 7.6 to maintain maximum effectiveness at sanitisation, so it is crucial to keep a close eye on your water’s pH levels. If this is not done, in addition to being less effective at cleaning, excess levels can cause eye and skin irritations.

Chlorine is stabilised by the use of Cyanuric acid, which gives you a residual slow-release of the active ingredients of the chemical to sanitise your swimming pool or hot tub water over a longer period of time. Chlorine is destroyed by UV light however, so it needs to be added to your pool or hot tub water on a regular basis.

When bacteria, algae and debris from poor maintenance bind with chlorine, it forms  Chloramines (Chlorine + Nitrates and Ammonia) – this is the cause of the typical “chlorine” odour in pools and renders chlorine less effective.

All in all, chlorine is still one of the most popular and effective sanitising agents and is less expensive than most other pool cleaning products.

Key Facts About Bromine

Bromine (interchangeable for the average person with the term ‘bromide salts’ in the context of water sanitisation) became popular in the 1980’s because of its fast acting effectiveness in cleaning pools, spas and especially hot tubs. It is considered by many to be the most efficient method of sanitising water, but can be slightly more expensive than chlorine.

It must be noted that once you add bromine, you cannot then change to chlorine or another chemical unless you drain the swimming pool or hot tub entirely, since this will cause an adverse interaction in the chemical’s structure.

These are the key benefits of using bromine for cleaning your pool or hot tub:

•               Bromine does not require as strict a pH level as chlorine – it can work extremely effectively with a pH of 7.0 to 8.0.

•               Bromine combines with debris to form Bromamines, which have little or no halogen odour and are just as effective at killing bacteria and other pollutants as the bromine sanitizer itself.

•               Bromine deteriorates in UV light, but in contrast to chlorine the bromines remain in the water, continuing to sanitise while not giving off an odour.

•               Bromine needs to be released by an oxidising (releasing) agent such as chlorine. The use of liquid chlorine (Sodium Hypochlorite) to oxidise the bromine sanitizer does not cause cyanuric acid build-up however, as in the case of using chlorine products.

•               Bromine has no taste or smell (important to females as this means that unlike chlorine it will not transfer a chemical odour to hair) and has less tendency to cause eye or skin irritation.

The Importance of Shock Treating Your Pool of Hot Tub

Whether you opt for chlorine or bromine to keep your pool or hot tub sanitised, a shock treatment will be required on a regular basis to boost the chlorine or bromine levels. The frequency you will need to administer a heavy dose of chemicals will depend on how often and how many bathers use your pool or hot tub as well as the weather. As mentioned above, you will also need to administer a shock treatment if the water has been out of use for some time, such as during the winter months.

Even if your pool or hot tub looks clean and clear, it is advisable to give it a shock treat every week or two. In addition, if you notice algae or if the water becomes murky, you should immediately undertake a shock treatment.

If you use bromine as your sanitizer, you can give the water a shock treatment using Calcium Hypochlorite, which is an unstabilised form of chlorine. However if you are determined to maintain a chlorine-free pool, an oxygen shock is highly recommended.

When it comes to chlorine pools and hot tubs, a shock treatment will not only pack a powerful punch in destroying bacteria and algae, it will also remove the Chloramines (chlorine which has been rendered less effective by bonding with pollutants) from the water by breaking them down into a gas form that will dissipate from the water.

Conclusion

This article is a general guide explaining the use of chlorine versus bromine as the primary  pool chemicals used to keep your water clean. There are a variety of alternative methods and products on the market however, so it’s advisable to have a chat with your pool or hot tub supplier to explore all the available options.

About the Author: Andrew Astonville is an independent advisor on maintaining swimming pools.