Winterise your pool

If you have not winterised your pool before, or you have doubt about carrying out the procedure, please contact us and we will be happy to carry out the job for you.

If you wish to undertake the work yourself the guidelines provided below will lead you through the job, it is not difficult however it does take a little time so make sure you aren’t in a rush.

Step 1

Thoroughly backwash the filter (see our page on how to backwash a filter if you are unsure how to do this) 

Step 2

Remove any debris from the pump strainer pot, skimmer baskets and pool water surface 

Step 3

Check the pH and adjust to 7.0 

Step 4

Shock dose the pool to 8 – 10 mg/l using an unstabilised chlorine such as Fi-clor Superfast Granules (see our page on treating a green pool for help with this).
This will kill algae and other harmful organisms that may be present. Allow the water to circulate for 3 – 4 hours to ensure thorough mixing before continuing.

Step 5

After shocking the pool check and adjust the pH to 7.2 

Step 6

Close the valve/s from the skimmer/s and lower the water level to 5 – 7cm below the skimmer level. (It is important to heed any recommendations made by the pool installer and not lower the water level too much. This is especially important if there is a naturally high water table as this could present structural hazards to the pool shell). 

Step 7

With the pool water still circulating via the bottom drain add algaecide pouring it evenly around the pool at a rate of 1 litre per 34m³ (7,500 galls).

Step 8

Leave the circulation running for 3 – 4 hours to ensure thorough mixing. 

Step 9

Remove ladders, diving boards and summer cover and store away from extremes of temperature. 

Step 10

Switch off and isolate the electricity supply. 

Step 11

Drain water from the pump, filter and heater, taking care to retain any ‘o’ rings from unions 

Step 12

Disconnect the pump and store in a dry place away from the extremes of temperature 

Step 13

Leave any valves above water level open, those below should be closed and protected against frost 

Step 14

Using strong cord or thin rope join and 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 should the pool freeze 

Step 15

Cover the pool with a heavy-duty winter cover (these are available from us) 

Step 16

Check the appearance of the water, the pH and Chlorine occasionally during the winter. If the winter is mild, add another dose of algaecide in February.

* Using a salt solution to weight the containers will avoid the contents of them also freezing 


Copper is a well established and excellent long lasting algae control product.
Acidic pH waters generally hold minerals (including copper) and salts in solution.
Alkaline waters, especially over 7.6 tend to lead to copper staining as minerals (including copper) and scale come out of solution.
When adjusting pH upwards whether purposefully or indirectly (e.g. when using shock products), sometimes unused copper can precipitate out and cause greening to the pool water. This is not slimy and therefore should not be mistaken as algae.
Bear in mind that rainwater dilution is inclined to be acidic, whilst sodium and calcium hypochlorite products, often used to shock, are alkaline.