Off-Season Care for the Sunbelt Pool

winter-pool-in-dallas-texasIf you live in an area where you don’t winterize the pool, but don’t use the pool during winter – you are by my estimate, about 35% of the pool owners in the U.S….

You still need to run the filter everyday, and maintain good pH and chlorine levels. Black algae can grow in a winter pool, taking advantage of the situation (dirty pool, low chlorine, little filtering).

Salt Chlorinators in Winter

If you didn’t know, you may be surprised to know that salt systems don’t produce chlorine when the water temperature gets too cold. It’s not that they can’t, but it’s very inefficient, and strains the salt cell. For this reason, many manufacturers have a fault built-in, to shut off the chlorine production at water temperatures below 60°.

pool chlorine types, pool chlorine tablets or trichlor tabsSo, what’s a salt pool owner to do? Use other forms of chlorine, the best being 3″ chlorine tablets, used in a chlorinator or in a floater. You may also want to shock the pool during winter, using Cal Hypo, or Di Chlor, which is stabilized, to last longer in an uncovered pool.


As the water temperature drops, water clarity can be maintained with less filtering, and less sanitizer. At water temperatures below 60 degrees, algae can still grow, or particulate matter can make the water cloudy, but as the water cools into the fifties, very little is happening.

At water temperatures of 70°F, run the filter at least 8-10 hours daily, to ensure a full turnover – that is, all the water in the pool having passed through the filter and returned to the pool. As the water cools to 60°, you can cut back filtering further, to save energy – but pay attention to the weather reports for frost warnings!

Pumps On in Freezing Temps!

snowflakeJust about every part of the U.S. gets freezing temperatures at one point or another. For a large part of the south, there is usually a period of a few weeks, or sometimes several periods, where night time (and day time) temperatures dip below the freezing mark.

During freezing temperatures, the pump must be running, and all lines (valves) should be open to keep water moving through the pipes and equipment. Fountains, slide water or water features should also be running, at least on low speed.

Intermatic makes a digital timeclock PE153PF that includes freeze protection. An air temperature sensor can turn on your pump when temperatures get close to freezing.

danger-ice-unsafeOr, you can run the pump at night during winter, and run it 24/7 for those periods where freezing is possible. If you’re too chintzy with electricity, a cold snap could cause major damage to pumps, filters, heaters and pipes – when air temps reach 32°, and water is not moving, severe damage could occur in less than an hour.

If you have a power outage from an ice storm, or during freezing temperatures; high tail it out to the pool equipment pad and pull the drain plugs on the pump, filter, heater, etc, and shut the power off at the breaker. Lay heavy blankets over the equipment to hold in any heat. When power is restored, quickly tighten drain plugs, prime pump and start up the system again.

Covering the Winter Pool

If your pool is a simple shape and size, covering it during winter with a safety pool cover could be an economical convenience for the sunbelt pool.

  • Looks great with a tight, snug
  • Safety cover protects kids and animals.
  • Durable covers have a 12 year warranty.
  • Covered pools need less filtering and sanitizer.


There you have it sunbelters – a few things to consider while you are sipping your tall daiquiris in the sun all winter long! Take care of your pool this winter, and avoid the dreaded black algae, damage to your pool surfaces and expensive repair bills from frozen pool equipment.

Davy Merino
InTheSwim Blog Editor


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