Preparing Pool for Cooler Months - Further Reading

Preparing Your Pool for Cooler Months


Some pool owners live in climates where a pool can be left open throughout the year. Below are tips for what to do when the swimming season is over and the pool becomes a water feature.

Water Chemistry

  • Change nothing except for the amount of liquid chlorine required because free chlorine consumption slows down dramatically.[1]
  • Once the water temp drops to between 50F and 60F depending on the SWG, the SWG will shutdown. At that time, you use liquid chlorine following the non-SWG targets on the FC/CYA Chart to maintain your free chlorine levels.
  • As the sun angle is so low, you will lose very little free chlorine each day.
  • Checking free chlorine once a week should be sufficient when the water temperature is below 60F.
  • If you have a plaster pool watch your Calcium Saturation Index as the water gets colder and use pH adjustments to keep CSI above -0.3

Pump Run-Time

  • You can minimize pump run time and only run it as needed to keep chemicals mixed
  • Turn on the pump with really low temp drops and hard freeze nights/mornings
  • Don't rely on Freeze Protection to turn your pump on. It may fail on you.
  • Some pumps like the Hayward EcoStar have low temperature protection for the drive and not Freeze Protection.

Skimmer Settings

  • Leave the skimmer/drain settings the way you have them as surface skimming is most important

Leafs Clogging Skimmers

  • If you have trees dropping leafs in your pool you may find your skimmer clogging and starving your pump of water. Consider some type of skimmer leaf guard


  • Heat Pumps will not run below 50F degrees
  • Corrosive condensation can damage many gas heaters if they are cycled with with water below 70F degrees. Using your heater to keep pool water above freezing can damage the heater from Heater Condensation
  • If you run your gas heater with water below 70 degrees it should be done in one cycle to get your water up above 70F. Then keep it above 70F using the heater if desired.
  • Do not plan to use your heater to keep pool water above freezing

Covering the Pool and Equipment

  • Solar covers can be used but you should allow the pool water to breath with the cover removed occasionally
  • Keep a tarp and plastic cover nearby to cover the equipment pad and protect the equipment from exposure in harsh weather like sleet
  • You can put an incandescent light bulb under the tarp to add a little heat if the temps are predicted to stay below freezing for several days in a row
  • Don't leave equipment covered for too long as it can become a nest for critter that can do damage

Equipment Cleaning

  • Clean the filter so that you do not end up with a clogged filter when the weather is bad

Contingency Planning

  • Take a few minutes now when the temps are still nice and warm to learn how to shut down everything and drain your system. You don’t really need to do everything, just learn how.[2]
  • A few years ago freak cold spells hit some of the south and left many pool owners without power for a few days. The only way to fully guarantee the pipes wouldn’t freeze was to drain the equipment pad as they couldn’t run their pumps due to no power.
  • It’s ALOT easier/enjoyable to learn how to do everything when it’s 80° outside than when it’s 30° outside.
  • Some people will have a spare pump that they can install should their pump fail during a freeze

The Physics of Freezing and Freeze Protection

To understand when you need to worry about the pool or equipment freezing read The Physics of Freezing and Freeze Protection.