When the bathing season is over and winter is coming on, you need to check your pool and its equipment. Precisely when to do this depends partly on where the pool is geographically and partly on the way the pool is used. Below some tips on what to do when the bathing season is over. Check whether the structure of your pool can withstand the water freezing. Under certain circumstances the surface of the water must be insulated and circulation must be maintained.
For pools that can withstand freezing:
Adjust the pH to 7.2-7.6 and switch off the pool heating.
Allow the pump to circulate the pool water and continue with reduced chlorination
until the temperature of the pool water falls below +7 °C.
The final shutdown procedure is as follows:
Brush down the sides of the pool and vacuum the pool thoroughly to make sure that it is really clean.
Backwash the filter thoroughly for 3 to 5 minutes. Then set the backwash valve lever to FILTER.
Switch off the electric power at the mains (fuse box).
If there is a pool ladder, take it out, wipe it off and store it in a dry place.
Remove the filter basket and flap lid from the skimmer. Then install an expansion flask or pieces of cellular plastic where the filter basket was located. These will take up the expansion of ice.
Remove the adjustable inlet nozzles (the balls). If the pump/filter unit is below the water level, install winter plugs where the inlet nozzles were removed.
Remove the lighting unit and store it in a plastic bag on the edge of the pool.
Drain the filter tank by unscrewing the drain plug in the bottom of the tank.
Remove the pump cover and take out the filter basket. Remove the drain plugs from the pump housing and the pre-filter housing. If the pump is outdoors, the motor should be removed and stored indoors.
Remove the pressure gauge on the backwash valve of the filter.
If the heater is not in a frost-free location, remove the drain plug. If there is no drain plug, disconnect the pipe coupling between filter and heater, so that all water is drained from the heater.
Add anti-algal agent as recommended on the pack.
Shock-chlorinate by dissolving calcium hypochlorite in a bucket of warm water and tipping it into the pool.
If the pool has steps, provide something around the steps to take up expansion which will shrink when the ice moves, reducing any strain on the steps. This could be a few plastic containers partly filled with a mixture of water and antifreeze (glycol), held in place with a weight.