top of page
  • Ocean Pools

Our Complete Guide to Swimming Pool Water Treatment: Water Chemistry, Chlorine, Bromine.

Maintaining high quality water in your pool is a vital part of a safe and enjoyable swimming experience and, to do this, your water must be treated correctly. In this comprehensive guide, we’ll look into all the most important features of water treatment that you need to know to keep your pool clean.

Clear water in outdoor pool

Water Chemistry

A brief understanding of water chemistry will go a long way in understanding successful water treatment. Here, we’ll outline what you need to know to maintain a harmonious balance for crystal-clear pool water.

Water Balance

For clear and safe pool water, the correct water balance is important. pH measures the acidity or alkalinity of pool water, the pH level plays a crucial role in the chemistry of swimming pool water, impacting the overall balance of other chemicals.


The acidity or alkalinity of water plays a pivotal role. Striking the ideal pH range between 7.2 and 7.6 is crucial. Deviating from this range not only affects water clarity but can also lead to skin and eye irritations.

Total Alkalinity (TA): 

Acting as a buffer, TA regulates pH stability and describes the water’s resistance to change in pH. Maintaining TA between 80 and 140 ppm ensures a stable and swimmer-friendly environment, preventing rapid pH fluctuations.

Calcium Hardness

The water we use for pools varies in calcium hardness across the UK. Understanding how calcium levels impact pool treatment is essential:

  • High Calcium Hardness: Can lead to scale formation, affecting pool surfaces and equipment.

  • Low Calcium Hardness: May result in corrosion, impacting the longevity of pool surfaces. Proper measures are necessary to maintain an optimal calcium hardness level for water clarity and equipment protection.

The calcium hardness level should be kept above a minimum of 200 ppm.

Pool Sanitisers

Pool sanitisers are required to maintain hygienic and safe pool water. A swimming pool is constantly contaminated by a number of different things from dirt and leaves to sun cream and deodorant and sanitisers prevent the build-up of bacteria and algae. We’ll go through the main sanitisers used in the UK, below:


Chlorine is the most common pool sanitation chemical and effectively combats bacteria and other contaminants. Chlorine comes in various forms that are safe for pool operators to use, from chlorine tablets to granules and liquids. Chlorine is a beneficial option for pool sanitation due to its widespread availability and its compatibility with a wide range of pool types.

Shocking the Pool

Regular pool use introduces increased organic matter that reduces the efficiency of sanitisers. In this case, shock treatment, or super chlorination, becomes necessary to burn off these contaminants and restore the effectiveness of your sanitiser. It’s important to note here though, that you should never mix swimming pool treatments together. They should always be added separately.


An alternative to chlorine, bromine offers effective pool sanitation with some distinct advantages. Known for stability in higher temperatures, bromine is particularly suitable for hot tubs and spas. Bromine is available in various forms, such as tablets and liquids, prioritising safety with diluted liquid forms due to its skin and eye irritant nature. Beyond its quality at higher temperatures, bromine has a few benefits over chlorine. Bromine is a less pungent alternative, so can be used to disinfect your pool without the strong smell associated with chlorine. Bromine is also more gentle on the eyes of swimmers using your pool.

UV Treatment

Ultraviolet (UV) treatment is a method of disinfecting pool water that has a number of unique benefits. The short-wave UV light instantly removes algae and bacteria, aiding in clear and clean pool water without needing additional chemicals. UV disinfection does not prevent algae growth on the surfaces of your pool but does come with a number of pros which make it a great option for a pool owner.

UV treatment systems reduce the chemical dosing you require to keep your pool clean. This reduces the cost spent on chemicals whilst making a nicer, more chemical free pool environment. Using a UV system can also reduce the wastewater you need to dispose of and reduces the backwashing of filters. These systems are also easy to operate and install and can be retrofitted to a variety of pools. On top of all this, UV treatment is relatively cheap to install and cost efficient to run. All in all, UV disinfection is a great option for treating pool water.

If you would like to find out more, contact us today at:

01902 670717


bottom of page