The Best Way to Close a Swimming Pool

Here is a great article on the best way to close your pool by Rob Cox


The Best Way to Winterize a Swimming Pool

Every swimming pool is different – different surfaces, sizes, shapes, and with all manner of pool filtration, heating and purification equipment. Winterizing a pool also has slight differences in procedure, depending on the equipment, but essentially doing the same thing.

If you’re new to pool winterization, it involves removing the water from the underground pipes and the aboveground equipment, and then cleaning, chemical-ing and covering the pool. That much is the same for all pools, but there are other principle tenets that apply to all pools, big and small.

Winterize before first frost, for best results.


  • Balance the pool water a week before closing. If you try to dump in 3 or 5 different chemicals within an hour, they may not adjust to desired levels, and they won’t have circulation to disperse well. This can damage your pool surfaces and lead to bad winter water quality. The best way to do it is to test and adjust a week prior to closing, and then test again just before you add your winter chemicals.
  • Shock the pool water 5-7 days before closing. After balancing the water, but several days before closing the pool. When shock is added to the pool at the same time as other chemicals, all sort of interference can happen, and what usually happens is that the shock interferes with other important winter pool chemicals, such as algaecide and stain & scale products.
  • Add Stain & Scale or Enzymes 24 hours before closing. Stain & Scale should be used if you have a salt pool, high calcium hardness levels, or metals in your water. Enzymes are great for pools in dusty rural or smoggy urban areas, or mesh covered pools that tend to open up green. These products both need to be circulated by the filter pump for at least 8 hours before closing, for best activation.
  • Clean the pool spotlessly, and clean up around the pool deck.
  • Backwash the pool filter thoroughly for around 10 minutes.
  • Remove DE grids and cartridges to hose off completely and chemically clean with filter cleaner solution or a diluted muriatic acid solution. After cleaning, store grids or cartridges inside filter tank, and secure filter clamp band tightly.
  • Lower the water level in the pool by using the filter pump, a small cover pump or siphon using the vacuum hose. Vinyl pools can use snap-on skimmer covers to close the pool without lowering the water.
    • 12″ below skimmer for safety covers
    •  6″ below skimmer for solid covers using a cover pump.
  • Add the best winter algaecide like Combat 60, by walking it around the pool, 16 oz per 10000 gals.
  • Use a heavy duty winter floater, filled with chlorine tablets, tied off on both sides of the pool with a long piece to twine, to keep it stationary.
  • Blow the lines out and plug the wall fittings with rubber expansion plugs, or threaded plug with o-ring.
    • Blow out the lines with a Cyclone, a small compressor, or a large wet/dry vac.
    • Put the air in at the skimmer, or at the pool pump, to force air through all the lines, and equipment.
    • Plug the lines tightly (skimmers, wall returns, cleaner lines, spa jets) to keep water out.
    • Remove all drain plugs from equipment and store in pump basket with pressure gauge.
  • Winterize skimmers by using a Gizmo to absorb ice expansion from water inside the skimmer.
  • Cover the pool tightly with a winter pool cover, secured to keep out leaves and debris, and handle strong winds and heavy winter weather.
    • Aboveground pools should use an Air Pillow, to break up the ice sheet that forms across the pool
    • AG pools should also protect from high winds with items like cover clips, cover seal or wall bags.
    • AG filter systems and hoses can be moved indoors, while inground systems stay outdoors.Pool Closing Pitfalls to Avoid: 
  1. Make sure all the water is out of the plumbing and equipment; lines are plugged.
  2. Balance your pool chemistry and shock 4-7 days before closing.
  3. Cover the pool when spotlessly clean, to prevent stains and conserve chemicals.
  4. Secure the winter pool cover tightly, to prepare for the worst winter weather.
  5. Don’t forget to shut off power to the pump at the breaker.

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