In countries with a colder climate like the UK the swimming pool needs to be prepared for the winter months. But even in warmer climates, you might discover that some of the following information is useful.

If you do not take the correct precautions over the colder months than you are liable to frozen pipes, cracked pump and skimmer baskets and ice over the water which in turn can cause other major costly problems to your pool or spa.

During the cold temperatures water expands when it freezes, meaning that if trapped inside pipes and equipment it will expand and crack them. PVC pipes, fittings and ABS plastic pump parts are most at risk, but soft copper heat exchangers are also in danger too.

Another problem which relates to seasonal winter closure is the potential damage from debris and algae. Although algae doesn’t grow well in low temperatures especially if its shielded from sunlight by utilising a Winter Debris Pool Cover, prolonged periods of stagnate water will aid its development.

Warmer Climates – Spain, South France, Italy, Cyprus etc

The best protection during the winter is to keep an eye on weather forecasts. When temperatures are predicted to drop near freezing, set the circulation to run 24 hours per day, preferably with your swimming pool heater on at the lowest thermostat setting. During other times it is best practice to switch your swimming pool pump system to a timer for approximately 4 hours a day. This is best staggered in 2 lots of 2 hour intervals so that the water is never left for long periods without any movement. It is also best to keep your heater on the lowest thermostat setting. Alternatively if the pool is kept heated throughout the year than it is swimming as usual.

For those who are fortunate to have a holiday home overseas than it may be useful to implement some of the best practice tips for pools situated in the UK as you may not be around to check on the pool on a regular basis.

Colder Climates – UK

Most outdoor pools in the UK are generally closed during the Autumn and Winter months. The winterisation of the pool requires some time to prepare and implement to avoid damage to the pool and to make the reopening of the pool in the spring that much easier.

The following steps which are in no particular order will help you make these preparations:-

1) Balance your pH levels – The inaccurate balance of your swimming pool water can harm the pool even when the circulation is off so before closing make sure the pH is between 7.2 – 7.6. This can be done using pH & Alkalinity chemicals.

2) Shock your pool – In order to disinfect the water over the winter months and to kill any present organisms and algae it is necessary to superchlorinate the pool to 10ppm with a stabilizer-free chlorine known as a shock treatment. A good shock chemical to use is Fi-Clor Superfast Shock. Allow the water to circulate for 3 – 4 hours to ensure thorough mixing. Do not leave tablets or floaters in the pool or spa during the closure as the water isn’t circulating and nor is the chemical. Extreme concentrations in one area can do both structural and cosmetic damage especially to liner pools.

3) Prevent algae growth – In one of the latter steps you will see it is necessary to drop the pool water by 6 inches below the skimmer. With the water still circulating via the bottom drain, add Fi-Clor Winteriser or Kleenpool Algicide. These long-term algae treatments combined with the use of a shock treatment will deter the growth of algae.

4) Cleaning – Dirt and debris left in the pool water during long periods will leave stains. If these are not removed these stains will be much harder to remove several months later. Utilise a swimming pool leaf net to catch these items before they cause too much damage and/or vacuum your pool using the waste line.

5) Turn off equipment – Once the chemicals are adequately circulated, make sure you turn off all the circulation equipment from their respective main electrical points.

6) Lower water level – As mentioned earlier it is necessary to pump some water out of the pool. We suggest you lower the level to 6 inches below the skimmer. When water freezes it can crack the skimmer and related pipework, so the idea is to lower the level to a point that rain water will not raise it back up to this area. You can empty water out of the pool by using a submersible pump. Please note it is not advisable to completely drain the pool of water as it might cause serious cracks in the surround. For those pools with liners you may see a ripple in the vinyl when empty and this will not smooth out completely when refilled.

7) Drain the lines and circulation equipment– In order to protect the equipment and plumbing from freeze damage it is necessary to drain the water from the pump, filter, heater and all exposed pipework taking care to retain any ‘O’ rings from unions.

8)Remove equipment – Remove ladders, diving boards, automatic pool cleaners and solar bubble pool covers and store them away from extremes of temperature.

9) Extra precautions – Put some dirt or gravel in an empty plastic bottle and leave it in the skimmer. Also using strong cord or thin rope, float several weighted and sealed polythene bottles (perhaps used 5kg chemical containers). Space these evenly down the length of the pool to absorb expansion of ice.

10) Cover the pool – One of the most important items to use over the winter is a winter debris cover. By utilising one of these it will inhibit algae growth and keep debris out of the pool.

Check the appearance of the water, and the pH and free chlorine occasionally while the pool is shut down. If the winter is mild, add another dose of swimming pool chemicals in January.