Pool Winterizing: Shock Treatment, Closing and Equipment Care

Adjust pH to 7.2-7.6, Total Alkalinity to 80-120 ppm, and calcium hardness to balanced levels. Closing a pool with unbalanced water causes scaling or etched plaster over winter.

Thoroughly vacuum the floor, brush walls, and clean the waterline. Remove all leaves and organic matter; decaying organic debris consumes residual chlorine and fuels algae under the cover.

Clean the filter so the media remains clean throughout winter: a sand filter gets a complete backwash and rinse, while a cartridge is removed and washed as the manufacturer recommends; the two methods are not interchangeable. Thorough preparation is the true foundation of successful winterizing.

Alongside testing and cleaning, we prepare a winter closing record: the latest water test results, recent chemical applications, filter condition and the equipment list. The information below directly affects both the closing decisions and the spring opening.

Chlorine products differ in composition and active content, so there is no universal grams-per-cubic-metre dose; calculate the shock dose from the current label of the product you use and the pool volume. The objective is thorough disinfection of dormant bacteria and algae spores before water temperatures drop.

Run the pump continuously overnight following shock dosing to ensure complete distribution throughout all piping circuits. Never mix different treatment chemicals together or add them one after another at the same point.

Allow free chlorine to fall to the level stated on the label of the winterizing product before adding it, as very high chlorine levels can react with some winterizing products and algaecides.

Whether shock treatment is needed at all depends on test results, water condition and the disinfection system in use; it is not applied automatically at every closing. Instead of one waiting period or fixed chlorine value for all pools, we read the instructions for the chlorine product and the winterizing product together. The timing of closing the cover should also be compatible with these products.

Depending on the product, winterizing formulations are designed to remain active at low temperatures over extended months.

Winter treatment products are available with or without copper; compatibility with the existing treatment system and pool surfaces is assessed separately. Because concentrations differ, the dose of one product is never transferred to another. These products help protect the water through the season and make spring cleaning easier; they do not protect the pump, filter or pipes against mechanical freeze damage.

Never drain the pool completely; an empty pool risks being lifted out of the ground by hydrostatic groundwater pressure or suffering liner shrinkage. On many skimmer pools, water is lowered approximately 10-15 cm below the bottom of the skimmer throats.

This general rule is not applied the same way to every pool. Groundwater level, lining type, steps, the skimmer or overflow system and the water support the cover needs all affect the decision; some cover types require water to stay at a specific level. We decide whether to drain the pool or lower water to a given line only after assessing this information together.

Insert rubber expansion plugs into return inlets and skimmer ports. In freeze-prone regions, install foam compensator bottles (Gizzmos) inside skimmers to absorb ice expansion pressure.

The non-negotiable rule of winterization is draining all water circuits completely.

Switch off power to the pump at the panel and relieve system pressure first. Then remove drain plugs from the pump hair-and-lint pot, filter tank and chlorinator cells, and drain a heat pump or heat exchanger according to the manufacturer's winter instructions. Store drain plugs safely in the pump strainer basket. Set multiport valves to the 'WINTERIZE / CLOSED' position.

A technician blows out underground suction and return plumbing lines using an air compressor, then seals them with expansion plugs. For un-drainable lines, use non-toxic propylene glycol pool antifreeze; never use toxic automotive antifreeze. Where equipment can be removed, pumps and chlorinators are stored in a covered, frost-free place after a qualified electrician or technician has disconnected them.

For electrical and pressurised equipment such as heaters, heat pumps and salt chlorinators, our technical team plans shutdown, draining, isolation and storage according to each device's own manual. Opening a running or pressurised system is not a user task; it is carried out by an authorised technical service.

Light-transmitting tarps invite algae growth regardless of chemical dosing.

Tension and anchor the cover securely across coping stones. Loose tarps flap in winter storms, accumulate windblown debris, and sag dangerously under water weight. Solid safety covers, correctly tensioned and anchored, give better protection and are manufactured to carry the load if a child or pet falls onto them; in gardens with children or pets this is a decisive safety criterion.

Pump standing rainwater and melted snow off the cover periodically. A properly anchored safety cover ensures that reopening in spring reveals clean, clear water rather than an unpleasant surprise.

No cover is a walkway or play area, and not every cover is suitable for winter. We follow the conditions in the cover's own product documentation for fixing, rainwater drainage and snow load. Forcing a frozen part, straining the system or moving accumulated load off the cover without control can injure people and damage the cover. Access to the pool area by children and unauthorised persons is controlled separately, independent of the cover.

Check cover tension after heavy storms and drain excess standing rainwater from the cover surface.

We plan the inspection interval according to the pool's location and cover type. After unusual weather such as storms, heavy snowfall or prolonged frost, an additional check is made without waiting for the planned interval. Cover condition, water level after rain, the pool surroundings and access safety are all part of these checks.

In regions with heavy snowfall, ensure that water levels beneath the cover have not risen above skimmer freeze lines due to precipitation ingress.

A pool properly balanced, shocked, drained, and covered in autumn usually reopens in spring with clear water within a few days. The test and maintenance records kept before closing show where water balancing should start. Taking winterization seriously in autumn reduces the workload waiting in spring.

You can share your pool type, location, cover and equipment list with us. In our assessment at Çilek Havuz, we clarify the scope of winter care and the work that requires technical service together with you.