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Small Pool and Large Pool Winterization Guide
publisherMAYGO
time2026/09/12
- Small Pool and Large Pool Winterization Guide
Small Pool and Large Pool Winterization Guide
1.Timing
Winterization should begin when the water temperature consistently drops below 15°C (59°F) , as most winterizing products become ineffective above this temperature. When the water temperature falls below 12°C (54°F) , algae and bacteria growth slows significantly, making it the ideal time to winterize the pool.
2.General Steps for All Pools
· Thoroughly Clean the Pool
Vacuum the pool floor to remove debris, brush the walls and waterline to remove scale deposits and grease residue, and empty and clean the skimmer and pre-filter baskets.
· Balance Water Chemistry
pH 7.0 – 7.4
Alkalinity 80 – 120 mg/L
Calcium Hardness 150 – 250 mg/L
· Shock Treatment
Perform a shock treatment with chlorine or active oxygen before winterizing to eliminate residual bacteria and microorganisms, typically running the filter for 24 hours.
· Add Winterizing Chemicals
After shutting down the filtration system, evenly add algaecide and winterizing products to prevent algae growth and scale deposits during winter.
3.Special Steps for Small Pools
Small pools include above-ground round frame pools, inflatable pools, and small-to-medium above-ground pools. Compared with large pools, the key differences in winterization are: equipment can be disassembled and stored indoors, water can be partially or fully drained, and cover installation is simpler.
· Lower the Water Level
Lower the water level below the return jet to prevent water from freezing in the plumbing. In regions with extremely low temperatures, the pool may be completely drained, cleaned, dried, and stored away.
· Disconnect and Store Equipment
Disconnect and drain the pump, filter, and all connecting hoses. Store fragile components in a dry place away from the cold. Remove the skimmer and any accessories attached to the threaded filter connector.
· Ensure Complete Drying Before Storage
Ensure the pool and all components are completely dry before storage. Place the pool liner and accessories in cardboard boxes and store them in a dry environment between 15°C and 38°C.
· Use a Winter Float
Place an inflatable item (such as a pool pillow/air pillow) on the water surface to compensate for the space between the water level and the top rail, absorbing pressure from ice formation.
· Install a Winter Cover
Choose a sturdy, opaque cover to prevent debris from contaminating the water, limit evaporation, and reduce algae growth. For small above-ground pools, secure the cover with ropes and tensioning devices.
3.Special Steps for Large Pools
Large pools mainly refer to in-ground pools and large above-ground pools. The key to their winterization lies in freeze protection for the plumbing system.
· Lower the Water Level
Lower the water level to approximately 10–15 cm (4–6 inches) below the skimmer opening, but never fully drain the pool. Complete drainage can cause structural damage to in-ground pools due to surrounding soil pressure.
· Blow Out the Plumbing Lines
Use an air compressor or blower to expel all residual water from the plumbing lines. Push air from the pump end toward each return outlet to ensure all water is removed. This is the most critical step for large pool winterization — residual water freezing can burst pipes.
· Install Winterizing Plugs
After blowing out the lines, install winterizing plugs (expansion plugs) at each return outlet and skimmer. The tapered design and wing nut allow the plug to fit various port sizes securely.
· Drain and Protect Equipment
Turn off the filter pump and drain water from the pump, filter, heater, and other equipment. Remove drain plugs and store baskets and other components indoors. Heaters should also be drained.
· Insulate Exposed Pipes
Add insulation to exposed outdoor pipes and equipment using insulation foam or pipe insulation wraps, sealing joints with tape. If a pipe has already frozen, close the valve and gradually pour warm water over it wrapped in a towel. Never use open flame or boiling water directly.
· Install a Winter Cover
Use a sturdy, opaque winter cover designed specifically for cold seasons. For in-ground pools, a safety cover or heavy-duty winter cover with grommets is recommended, ensuring the cover overlaps the pool edge by approximately 1.5 meters (5 feet) for complete coverage. Use water bags to weigh down the cover edges if necessary.
· Regular Monitoring
Even a properly winterized pool requires regular checks: inspect the cover after heavy rain, check the water level to prevent overflow from rainfall, and tighten the cover edges and straps once a month.
Proper winterization effectively prevents freeze damage, protects the pool structure and equipment, makes it easier to reopen in spring, and reduces maintenance and repair costs.