• Vinyl Lined: 1 inch (25 mm) below skimmer mouth or tile line, whichever is lower.
• Plaster finishes with solid material cover: 1-6 inches (25-152 mm) below the skimmer mouth or tile line, whichever is lower.
• Painted or Natural Finish with solid material cover: 6 inches (152 mm) below skimmer mouth.
• With No Cover or Mesh Cover: 1824 inches (457-610 mm) below skimmer mouth.
• With Automatic Cover: water should be no lower than the bottom of the skimmer mouth.
Many service professionals feel that the less water drained from the pool, the less damage you will create to liners, plaster, and other cementitious finishes from prolonged atmosphere exposure. Higher water levels also mean less stress on covers. However, water levels should not be allowed to rise above the tile line of the pool to prevent damage to those surfaces during the winter.
Covers
Prior to installing winter covers, ladders, diving boards, and handrails should be removed, cleaned and then stored in a dry place. In Chapter 10-3 of the APSP’s Service Tech Manual, 4th Edition, the four main types of winterizing covers are discussed:
• Solid Lightweight Fabric Cover: Constructed of a solid film or sheet of synthetic fabric, held down by water tubes, sandbags, or ropes and anchors.
• Spring-loaded ASTM Mesh Safety Cover: Made of mesh fabric, usually anchored to the pool deck.
• Spring-loaded ASTM Solid Safety Cover: Made from reinforced vinyl fabric, usually anchored to the pool deck.
• Automatic and Manual Safety Covers with Tracks: Made of solid fabric; available in standard and custom sizes.
All covers, regardless of type, have advantages and disadvantages. The type of cover and the level of the water in the pool must be closely examined over the winter season to prevent problems.
To avoid a safety hazard, solid covers should have automatic cover pumps which remove water from rain or melted snow (see Precautions below).
On all covers, leaves and other organic debris must be periodically removed to prevent plugging the cover pump or damaging the cover.
Tracked solid covers must be monitored for accumulation of water, snow, and ice. Excess weight from these items can damage the track system, possibly damaging the concrete, coping or pool wall.
With all winterizing covers, the long-term durability and longevity of the cover is dependent on proper water balance, proper water levels under the cover, regular maintenance and cleaning.
Precautions
As with all chemical application to pool water, proper safety considerations must be followed. Do not mix chemicals. Follow manufacturer’s directions for the proper use of chemicals including the correct time to add winterizing chemicals to avoid damaging surfaces, covers, and equipment.
When cleaning out chemical feeders, exercise caution and wear the proper safety equipment such as gloves and safety goggles. Check with manufacturer regarding disposal of chemicals from feeders.
Properly shut down and clean filters. It is not recommended to clean DE grids and cartridge filters with muriatic acid solutions and then store them for the winter. The acidic residual may stay in the grids or cartridges and degrade them while in storage. After any acid rinse, rinse thoroughly with water to remove any acid residue and allow to dry completely before storage.
Avoid overfilling water tubes that are used to anchor some types of covers to avoid splitting the tubes during freezes. Do not use masonry blocks, bricks, or concrete stepping pads to hold down covers as they could fall in the pool and damage the interior finish of the pool.
Never use ethylene glycol based (common automotive) antifreeze in winterizing pool equipment and plumbing lines. Always use a pool formula antifreeze or a propylene glycol-based product. Antifreeze should be used sparingly to avoid problems when opening the pool in the spring.
WARNING: All solid safety covers must meet ASTM F1346-91 (2010), “Standard performance specification for safety covers and labeling requirements for swimming pools, spas and hot tubs” and have an automatic means of preventing water accumulation on top of the cover whenever the pool is covered. For example, this may be accomplished with a drain panel or a pump. Rain water on the cover is a drowning hazard for children.
Consumers must be made aware of the necessity of preventing water accumulation on top of the cover.
Only cover a pool when the water analysis indicates the chemical parameters are within the cover manufacturer’s recommended ranges.
After adding winterizing chemicals, follow label instructions for the disposal of any remaining chemicals. General Description
The techniques and methods in closing down an in-ground pool for the winter vary from region to region. Local climate conditions and customs often dictate the type, amount and timing of maintenance and services that are performed on an individual pool.
Even with regional differences which are often dictated by the severity of the winter season, most winterizing procedures share several common features that can be used to protect pools regardless of the type of interior finish and structure. Winterizing or closing should occur before the first hard freeze.
Conclusion
The degree of complexity associated with winterizing an in-ground pool is dependent on many factors. From an environmental or climatic perspective, the expected temperature range, the amount of precipitation and the depth of the frost line will all dictate what actions and processes must be done to avoid damaging the tile, interior surfaces, plumbing, equipment, and structures.
One should consult with the various chemical manufacturers, pool manufacturer or builder, equipment manufacturers, and cover manufacturers for the correct procedures and processes to use in a geographic region.
