>> FAQ - Swimming Pool Online advice and recommendations Winterize your pool safely - all you need to know

Winterize your pool safely - all you need to know

The recommendations detailed below apply to pools with a traditional filtration system, ie with a filtration pump and filter situated in a technical shelter.

Why winterize my pool?

Climatical conditions have a direct impact on outdoor pools. Winterizing allows you to protect your pool material from restrictions linked to negative temperatures during the winter months.
Good winterization facilitates the startup of your pool in Springtime.

When should I begin the winterizing process ?

When your pool water arrives at a temperature of 12°C you should winterize. This is the ideal temperature for your treatment to be efficient and long-duration, to ensure algae and bacteria development is limited to a minimum.

Which type of winterizing method should I use?

Two options are possible :

- Inactive winterizing - this entails totally stopping your filtration system and other pool equipment during the winter months.

- Active winterizing - programming the filtration system to operate for several hours per day coupled with the use of a frost protection unit.
Winterize your pool

Inactive winterizing

Inactive winterizing consists of stopping all pool organs during the winter months.

Until the water temperature has not stabilised to below 12°C do not stop your filtration system or treatment as algae and other microorganisms will continue to develop.

Thoroughly clean your pool

First and foremost you must clean your pool, removing all dirt and debris, leaves and the pool water line.

Lower the water line

The next step is to lower the water line of your pool to 10cm below the discharge nozzles.

Warning : do not under any circumstances totally empty your pool as this could cause irreversible structural damage.

Water line of pool during winterization

To lower the water level:

If your pool is equipped with a main drain coupled with a sand or DE filter :
- position the multi-way valve to "backwash",
- close the valve or valves connected to the skimmer circuit,
- close the valve connected to the brush adaptor,
- open the valve connected to the main drain,
- open the used water drain valve (if you have one),
- start the filtration pump and supervise the water level till it lowers to below the discharge nozzles.

This procedure allows you to lower the waterline to 10 cm below the discharge nozzles and backwash your filter at the same time. If you use a DE filter, the DE present in the filter tank should be removed before winterization.

Once the required level has been reached :
- stop the pump,
- close the main drain,
- selection the position "filter" on the multiway valve,
- open the skimmer valves and brush adaptor valves,
- start the pump to purge all remaining water present in the piping network into the pool
- Let the pump run for around 5 mins till all water evacuating into the pool stops

Stop the filtration system and apply the winterizing product

- stop the filtration pump,
- remove the bearings from the discharge nozzles and insert Winterizing plugs in their place
- insert a winterizing plug into the brush adaptor
- remove the skimmer baskets, insert a gizzmo into each skimmer, screwing into the skimmer mouth as to prevent water from returning to the piping network. If this proves to be difficult, put a winterizing plug and then a gizmo into each skimmer mouth.

Then add the winterizing product following the manufacturer's instructions. This product prevents the development of algae and fungi, limescale build-up and mineral deposits. This ensures an easy start-up of your pool in Springtime.

Protect your pool from frost

To avoid frost damage to your pool structure, you must position floaters diagonally in your pool. These floaters can be compressed, so ice formed on the water surface will compress against the floaters and not the structure of your pool (a cause of serious structural damage).

Sand filter
Sand filtration system
Multi way valve
Multiway valve in backwash position
Flood pump
If you don't have a main drain,
use a flood pump

Multiway valve in filtration position

Multiway valve in filtration position
Main drain valve in closed position
Skimmer and brush adaptor open

Gizzmo and plugs
Gizzmo and winterizing plugs
Positioning of winterizing floaters

Use a winter cover on your pool

If you have a winter cover you should position it following the manufacturer's instructions.

Winterizing pump cap
Winterizing the filtration pump consists of opening the cover of the prefilter, cleaning the basket, unscrewing the purge plugs (in general under the prefilter on the body of the pump). To avoid losing the plugs, place them in the prefilter basket before replacing it.
Winterizing filter cap
If your filter features a purge plug (do not confuse with the sand evacuation valve which is larger in size) open and purge, ensuring correct evacuation of water from your technical shelter.

If your technical shelter is situated above the water level of your pool open all valves to 1/2 position and position the multiway valve to the winterizing position. If your multiway valve does not feature this position, place the lever between 2 positions to avoid the inner joint from hardening when out of use.

If your technical shelter is situated below the water level of the pool, close all the valves and position the multiway valve to closed position.

Winterizing position
Technical shelter above water level
valves 1/2 closed
Multiway valve in Winter position

Closed multi valve position during winterizing
Technical shelter under water level with valves closed
Multiway valve in closed position

Finally Disconnect your electrical box.

Your pool is now winterized. Concerning additional equipment, such as electrolysers, booster pumps etc... refer to the manufacturer's instructions.

Active winterization

Active winterization consists of activating the filtration system of your pool during the winter months.

By choosing this method, the quality of your pool water is preserved, the pump is protected against seizure caused by being out of service for too long and the pool continues to be an attractive element in your outdoor environment. There will be no "deep clean" required during the Springtime or the requirement to purchase expensive chemicals to start up in springtime.

If you choose this method you are required to continue cleaning your pool and most importantly, supervise the filtration system during periods of frost. That is why we strongly recommend the use of a Frost protection box which will operate the pump when the ambient temperature presents a risk for the filtration system.

If you live in a region subject to hard frost during the winter months, place a line of floaters in your pool and install gizmos in the skimmers, close the skimmer and brush adaptor circuit valves, open the main drain valve leaving the discharge valve open. Your filtration system will continue to operate, protected against frost.

Once the period of frost is over, remember to put your skimmers back into service.

Multiway valve in filtration position
Multiway valve in filtration position
Main drain open
skimmer and brush adaptor closed

You can start with active winterizing switching to inactive winterizing by following the above steps.
Photos non-contractual