Pool Winterization
Professional winterization of the swimming pool is essential to ensure that everything operates perfectly in the next season. The lack of careful preparation can lead to severe, even million-forint structural and mechanical frost damages. Below we present the exact process, purpose, and steps of winterization.
The Result of Professional Winterization:
- Structure and liner protection: We protect the pool body from the expanding force of ice.
- Pipe system protection: We prevent underground pipes and fittings from freezing and bursting.
- Mechanical safety: We protect expensive pumps, filters, and auxiliary equipment.
- Long-term water quality: The pool water remains clean and algae-free during hibernation.
Important rule: Winterization should only be performed when the pool water temperature drops permanently below 15°C. At higher water temperatures, the efficiency of winterizing chemicals decreases significantly, and microorganisms and algae can multiply rapidly.
Step-by-Step Winterization Guide
1. Preparation and Cleaning of the Pool Body
A pool should only be winterized if the water is already completely clear and transparent. As the first step of the process, vacuum the bottom of the pool thoroughly and clean the walls – with special attention to greasy, limescale deposits accumulated along the waterline. If you leave the pool dirty, you will face almost unremovable stains and stubborn algae growth during the spring opening.
2. Water Level Adjustment and Frost Protection
After cleaning, the pool water level must be lowered below the bottom rim of the skimmer (filtration mouth) by approx. 5–10 cm. This ensures that water cannot freeze into the skimmer housing.
Alternative solution (Gizzmo): If you do not wish to lower the water level, you can use a so-called Gizzmo (a pipe-shaped ice-absorber) to protect the skimmer, which must be screwed into the skimmer thread. In this case, however, you must take into account that precipitation and freezing can cause the water level to rise critically during the winter months.
After lowering the water level, return inlets and suction nozzles must be hermetically sealed with tapered, rubber winterizing expansion plugs. This prevents the water in the pool from flowing back into the underground pipe system, where it could freeze into ice and rupture the conduits. To compensate for the expansion of pool water, ice-absorber blocks (expansion cushions) must be placed on the water surface, linked together both longitudinally and crosswise. When water freezes into ice and its volume increases, the pressure compresses the flexible frost cushions, so no destructive expanding force is exerted on the pool's side walls.
3. Chemical Balance and Winterizing Liquid
Before sealing, it is essential to adjust the chemical balance of the water:
- Adjust the pH value strictly between 7.2 and 7.6.
- Raise the free chlorine level (via shock chlorination) to 3–5 mg/l.
- If the water is slightly cloudy or contains algae, use a flocculant (coagulant), then vacuum out the settled debris.
Only after adjusting the above values and thoroughly mixing the chemicals can the special winterizing liquid (winterizer agent) be poured into the water. The required dosage is determined by the local water hardness, which can be read from the table on the product label. The winterizing fluid prevents the formation of hard limescale deposits and the proliferation of fungi and algae. During spring opening, the water may be slightly cloudy or foamy – this is a completely natural phenomenon; the residues of the chemical decompose biologically within one to two weeks after starting the filtration cycle and adding fresh water.
4. Removal of Accessories and Covering
During winterization, all metal and plastic accessories – such as the stainless steel ladder, diving board, and handrails – must be dismantled from the pool. The anchor sockets must be closed with winter plugs or protective caps. Finally, the pool body must be covered with a heavy-duty, light-blocking winter safety cover. This cover extends significantly beyond the pool rim, completely sealing off the water from winter storms, fallen leaves, and snow. The underside of the cover is always dark (black) – this side must face the water, as by completely excluding light, algae are unable to photosynthesize and multiply. The edges of the tarp must be tied down with tension ropes or weighted with water bags or sandbags so that strong winter winds cannot get underneath.
Mechanical Winterization
Draining the water from the mechanical units is a critical point, as even a minimal amount of water remaining inside can rupture expensive equipment:
- Sand filter tank: Before lowering the water level, perform a thorough backwash and rinse cycle. Following this, drain the entire water volume by unscrewing the drain plug at the bottom of the tank. Set the multi-port valve to the "WINTER" position to relieve stress on the internal seals.
- Pool pump: Unscrew the drain plugs of the pump housing, let the water drain, and clean the lint/hair strainer basket. It is recommended to disconnect the pump from the system and store it in a dry, frost-free place (e.g., basement) until the spring season.
- Lighting and automation: If the pool light fixtures fall within the winter water level height or the frost line, the spotlights must be dismantled from the wall niche and safely submerged to the pool bottom (depending on cable length), or wiped completely dry and packed away.
- Dosing systems and power-off: Automatic chemical dosing systems and salt chlorinators must be drained, and their measuring probes (pH and Redox) must be hibernated in a frost-free room, placed in specific storage solution liquid. Finally, the entire control panel must be disconnected from power by turning off the main circuit breaker.
Completing these steps precisely guarantees that your pool shell and reinforced membrane survive the freezing temperatures intact. If you encounter any structural issues during the process, a professional pool liner installation or renovation can fix any faults before the next season starts.
Need Expert Assistance?
Whether you are dreaming of a new pool, modernizing your mechanical system, or optimizing water treatment, we help you choose the most optimal solution. With our service department and years of experience, we guarantee that your pool will bring joy to your family for many years to come.
Contact us and request a quote today!
Our additional professional pool technology services and products:
- Pool liner installation – Precision installation of durable, UV-stable, and perfectly watertight reinforced membranes.
- Pool construction – Turnkey engineering design and structural execution of Porocell and shuttering block pools.
- Pool enclosure – A wide selection of high and low-profile, easily retractable polycarbonate structures.
- Pool shutter – Automated safety cover systems with thermally insulated slats floating on the water surface.
- Pool roller shutter – Aesthetic, recessed, or surface-mounted automated winding solutions.
- Pool renovation – Complex reconstruction of existing pool structures and outdated mechanical systems.
- Pool heat pump – Energy-saving, inverter heating systems for climate-independent swimming comfort.
