Pool Water Chemistry

Maintaining your pool water in a safe, balanced state can be a daunting prospect for new pool owners; the aim of this section is to explain in simple terms the few basic tasks that are essential for all pool owners. By closely following the guidelines in this guide your pool water will remain in pristine condition. There are no shortcuts. By carrying out a few simple tasks regularly you will ensure high quality swimming pool water. Basic pool water quality can be broken down into two basic categories:

Water sanitation

Pool water needs to be sanitised to ensure bather safety. Bacteria will rapidly multiply in pool water that remains unsanitised. Chlorine is highly effective at destroying potentially harmful germs; it is also a very effective product for destroying algae. It is, by far, the most popular form of sanitiser for pool water.

*Water Balance

pH being the most important factor for Above Ground Pools. pH is the measurement scale for the acidity and alkalinity of your pool water. Maintaining your pool within the ideal pH range of between 7.2 and 7.6 will ensure that your pool water is neither corrosive nor scale forming. Running your pool water outside the pH range of 7.2 and 7.6 will also result in skin and eye discomfort. It will also result in premature equipment failure.

Speciality Products

We recommend the use of Relax Algicide to assist the Chlorine in keeping your pool water clear from Algae. Use of Relax Liquid Clarifier will help to keep your water sparkling clear.

By regularly paying attention to the above, you are unlikely to encounter water quality problems. *This guide restricts Water Balance to pH control. More detailed Water Balance guidelines relating to Calcium Hardness, Total Alkalinity and Cyanuric Acid is available in our comprehensive Domestic Pool Owners Guide.

Find out the Water Volume in your Pool

You will need to know how much water your pool holds before you can determine the quantity of Water Treatment products your pool needs. Find out the water volume in litres rather than gallons; it’s easier to calculate the quantity of product required in metric rather than imperial. Your pool supplier should be able to supply you with this information, if not you can use the following guide.

Pool Water Volume Estimates

Consult the Pool Operation Manual supplied with your Above Ground Pool to determine the amount of water your pool holds. Several examples of the most popular pools are listed below

Which Sanitiser Should I Use for my Pool?

Your pool water may look crystal clear, but that does not necessarily mean that it is healthy. Your pool is constantly being polluted by the environment; dirt, leaves, pollen etc are introduced daily. Swimmers will also introduce pollution to your pool water, your filter will remove much of this debris, but you will need to sanitise your pool water to keep it clean. If you take a look around a Pool Shop, the chances are you will see up to 5 or 6 different types of sanitiser for your pool, some are chlorine based, others are non-chlorine. Each of the systems available has its good points, but they all have their drawbacks. For the vast majority of Above Ground Pools the most suitable sanitiser is Stabilised Chlorine Granules. This Guide assumes that you are treating your Above Ground Pool with Stabilised Chlorine Granules.

Stabilised Chlorine Granules (Dichlor) have the advantage of being fast dissolving and will not cloud your pool water when added. They are fairly neutral in pH and contain a stabiliser to minimise the amount of chlorine lost to sunlight. Being readily soluble they offer the advantage of allowing you to instantly increase the chlorine residual of your pool water.

For more information regarding the alternatives to Stabilised Chlorine Granules contact your local Pool Dealer.

How much product does my pool water require?

It is not possible to determine how much Water Treatment Product your pool needs without first knowing the following information:

The volume of your pool water - Preferably in litres.

Your Test Kit Results - You need to know the condition of your pool water before you can determine how much of a Water Treatment Product is required to adjust pool water to the optimum level.

The optimum level for your pool water - The following charts will enable you to determine what level you need to achieve.

Recommended Levels for your pool

pH Minus (Dry Acid)

As an example let us assume that your pool contains 10,000l (2,200gal) of water, and that your pool water test gives the following readings: Free Chlorine = 0ppm, and pH = 7.7

To increase the chlorine residual of your pool water to the maximum recommended level of 3 parts per minimum you will need to add 6g of Stabilised Chlorine Granules per 1000 litres.

If your pool holds 10,000l of pool water this will equate to 60g.

To reduce the pH of your pool water you will need to add pH Minus at a rate of 10g per 1000l of pool water. Consequently if your pool holds 10,000l of water you will need to add 100g of pH Minus per day until your Test Kit results indicates that the pH of your pool water is 7.4.

For a 10,000l pool you will need to add 100ml of Concentrated Blue Algicide initially, then 20ml every 2 weeks. Take care not to over-dose this product; use the calibration marks on the side of the bottle to ensure that you dose the correct amount.

Caution - Never mix any swimming pool water treatment products together. Each product needs to be added to the pool water separately. Always add granules to water, never add water to granules.

How long do I need to wait before I can use the pool?

Pool professionals usually advise that swimming be suspended for a 30-minute period after treating your pool. Never add Water Treatment products while the pool circulation pump is turned off; you will need to operate the circulation pump for a full 30-minutes after treatment. Under no circumstances add any water treatment products while the pool is in use.
If you are “Shock Treating” your pool with chlorine you should wait until the chlorine residual drops to below 5ppm before allowing the pool to be used. After shock treating your pool water leave your Pool Cover off until the Chlorine residual has reduced to 3ppm (parts per million).