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10 Off Season Pool Care Tips

By Matt Giovanisci | Updated: December 3, 2013

Unfortunately, the responsibilities of pool ownership don’t end when swimming season does! It’s important to continue caring for your pool during the off-season (fall, winter, and early spring) to ensure a successful and clean opening.

1. Add a Mid-Winter Algaecide

Use an algaecide or algaestat (preventive), particularly one that stays in the water for a good length of time.

On the last day of operation, add this to the water and run the pump for 24 hours to fully circulate. Then shut down the circulation system for the winter. By keeping the green stuff away as long as possible, pool startup will be much easier.

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2. Check Your System to Prevent Freezing

As winter approaches and you plan to close the pool, remember to check your pipes and motorized parts. Drain the water from the pump, pool heater and filter. You also want to drain the water 4–6 inches below the pool skimmer.

As the temperatures begin to dip to freezing levels, any excess water in these parts can freeze. If that happens, the pipes can crack, which can cost serious money in the long run.

Remember to also completely remove any water that has accumulated on top of your pool cover to keep it from freezing. You can use a sump pump or a winter cover pump.

3. Keep Your Pool Cover Clean All Winter Long

You should absolutely have a winter cover for your pool. A dirty but safely covered pool beats a sparkling clean but uncovered pool any time. There simply is no better insurance for keeping toddlers and wildlife out of the pool.

If possible, keep the water level where it’s supposed to be, and the pumps running.

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4. Add Chlorine to Your Pool to Ensure a Clean Opening

We recommend a few things if you have a safety cover on your pool in Michigan or the Midwest United States:

  • In the fall, make sure to add chlorine and algaecide to your pool for over the winter. Don’t add too much chlorine though. If the chlorine level is too high over the winter, you can bleach the liner
  • As soon as the water thaws in the spring, pop open a corner of the cover and add liquid chlorine to the pool (1–2 gal. for an average in-ground pool). You can do this yourself, or hire a professional to do this for you. This is the most important step.
  • When your pool is opened, vac on waste to help remove the debris from the bottom of the pool. If you try to vac the sediment from the bottom of the pool and run it through the filter system, you may find that the sediment is so fine that it goes right through your filter.
  • If you find your pool is pea-soup green in the spring, add more liquid chlorine, allow your filter to do its work, and monitor the progress. Be patient. If you don’t see progress in several hours, repeated doses of chlorine and algaecide may be in order, and your pool may benefit from an extra vacuum session.
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Use the entire contents of the bag when opened. If any granules settle to the bottom of the pool use brush to disperse them. Add the right dosage of this product during evening hours while the filter pump is running.

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5. Check Your Safety Cover to Make Sure It’s Properly Fitted

Having clean, clear water in the spring makes your life much easier. One key element in achieving that is a properly fitted safety cover. It your pool cover doesn’t fit, it’s an invitation for dirt, debris, and even small animals to find their way into your pool.

6. Pay Attention To The Weather

If the fall has been mild and warm, it’s a good idea to check the pool and add more chlorine and algaecide just ahead of the colder season.

If you live in an area that has heavy rains in the fall and you use a mesh cover, much of the winterizing chemicals you use may become diluted. Then, just before the first big freeze hits, charge up the chemicals to help ensure the water makes it through to spring startup without an algae bloom.

7. Use Enzyme Chemicals to Break Down Non-Living Organic Contamination

Using an enzyme product during the off season (even poured through a mesh cover when the water is not frozen) will help to break down non-living organic contamination that will inevitably make its way into your pool during winter. Some of this contamination includes bird droppings, pollen, or even bather contaminants left over from your pool season.

An off-season enzyme will help prevent the waterline ring that can occur through the winter, which would normally require a lot of scrubbing in the spring.

8. Keep Your Above Ground Winter Cover Free of Debris

If leaves, sticks and other junk accumulate on your pool cover throughout the winter, you can end up with a nasty stew of stagnant water, which is a mess to remove and some of it often ends up in the pool.

Using an air pillow connected to the cover in the center of the pool not only protects your pool from snow and ice damage, it also disperses water and debris to the sides of the pool making cleaning easier. You want to keep some water on the cover to help stabilize the cover in the wind, but you don’t want any debris.

9. Keep An Eye On Your Above Ground Winter Cover All Season

Periodically check your cover cable to make sure it’s tight. If the cable becomes loose, the cover might start to slip into the pool.

Check your air pillow to make sure it still has air in it. If you see it starting to go flat, get another one, slip it under the cover, and blow it up.

10. Protect The Water and Open Early

Use a winterizing product in the water that has some biocidal properties to slow or prevent microorganism growth. The principles you follow in the summer also apply to the winter. If you can maintain proper pH sanitizer levels at all times, pool care becomes easier.

The challenge in cold environments is that water is not being circulated, the pool is covered, and a typical sanitizer like chlorine will degrade and disappear during the long winter. This is why many winterization products include algaecides that are stable and will stay in the water for extended periods of time. Most algaecides will survive the winter and slow or stop algae growth; some of these products may even slow bacterial growth.

Also, open the pool before the water gets too warm. If you wait until later in the spring to open the pool, you’ll likely have more algae growing in the pool.

Happy Swimming!

Matt Giovanisci is the founder of Swim University® and has been in the pool and spa industry since 1995. Since then, his mission is to make pool and hot tub care easy for everyone. And each year, he continues to help more people with water chemistry, cleaning, and troubleshooting.
A Cheat Sheet For Perfectly Balanced Pool Water and Crystal Clear Swimming
Download this FREE printable cheat sheet to keep your pool clean and clear without any fuss. You’ll never worry about your pool again with this easy-to-use guide.
Click Here For The FREE Cheat Sheet