Closing An Above Ground Pool

Closing An Above Ground Pool (1)

Anthony Barnes

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Pool season is over! Now you’ll have to spend more time indoors.

Don’t worry, though, because there are lots of other activities to enjoy during this cold weather.

Closing your pool properly is important. You should make sure you do it right away when the time comes – don’t waste a day!

When spring comes, you’ll want to open your pool again, of course – and every day you spend not preparing it is going to give you more trouble down the road.

Why It’s Important To Close And Winterize Your Pool Properly

Closing An Above Ground Pool

Closing pools is very important because we need to protect our pools from the cold weather even with a solar pool heater.

We also want to make sure we clean them out before we open them again. Closing your pool correctly requires you to follow certain steps.

You need to make sure you do these things before you close your pool.

These include using proper chemicals, making sure your pool is level, and checking your pumps regularly.

If the temperature drops below freezing, the pump will stop working.

To prevent this from happening, turn off the power supply to the pump before the temperature gets too cold.

Pool owners should consider closing pools during the winter months. Leaving pools open costs money and time.

Swimming is not required during the winter. Closing your pool properly takes time and effort.

You should clean your pool (see also ‘The Best Way To Clean Pool Tile At The Waterline‘) thoroughly before closing it. The last thing you want on opening day is a dirty pool.

Pool owners should run their filters and chlorinate their pools (see also ‘Raise Or Lower Level Of Pool Chlorine‘) until they are closed for the season.

Doing so will help them when they need to shut off their pools. Pool owners should do one last deep clean before winterizing.

Vacuum, brush down the interior, and skim any debris lingering around the surface.

This will prepare your pool for a final balancing before the winterizing process.

Cleaning The Pool And Accessories

The first step in cleaning your above ground pool is to remove the debris that has accumulated on the bottom and sides of the pool.

This includes leaves, sticks, toys, etc. You should also clean out the skimmer basket and pump intake screen. 

Once these items are removed from the pool, you may need to add a little bit of water to get everything moving again.

Then you can start scrubbing away with your brush or sponge. Be sure to keep an eye on the water level.

If you have too much water in the pool, you could end up washing away some of the chemicals that were used to treat the pool.


Skimmers are rectangular plates that sit on the sides of pools. They collect debris and hold them until spring when they need to be emptied.

Pool experts call them skimmers because they resemble the shape of a skimmer used by fishermen to scoop fish off the surface of the water.

Skimmers are necessary for keeping your pool clean. Covering them is recommended to prevent freezing. Drainage of your pool is also important.

If your above ground pool has a skimmer basket and an inlet filter, you should be able to get away with just one filter.

However, if your pool doesn’t have either of these features, then you’ll need two filters.

One for the skimmer and one for the rest of the water. You may also need a pump to circulate the water through both filters.

Pump And Filter

Pumping water is hard work, especially during the cold months. Your pump needs to rest for the winter.

Remove all drain plugs, and store them in the pump basket. Keep the pump, chlorinator and hoses inside a shed or garage.

Your filter is a holding place (or container) for all the gunk that it can pick up as it circulates through your water.

You’re going to want to drain it before storing it inside (no way do you want THAT stuff sitting for long).

If you have a multiport valve, set it to winterize and remove the drain plug.

Allow the filter to drain. If your valves have any extra features, like a sight glass, or a bleed valve, remove those as well.

If your filter is TOO heavy to carry inside, leave it as it is: outside with all drain plugs removed!

A cartridge filter should be used when you’re using a pool pump. It’s easy to use and clean.

Just take the cartridge out, put it in a bucket of pool cleaner, and rinse it out. Then, let it dry before storing it inside.

Diatomaceous Earth Filters should be left open during the winter months. They help prevent algae growth.

You should always remove any pool equipment (see also ‘Pool Equipment Enclosure Ideas‘) before storing your pool.

Your pool ladder needs to be taken down and stored away safely. Electronics need to be kept inside during the cold months.

Saltwater pools need to be drained before winter because they use chlorine generators.

Turning off power and gas to the system makes it much cheaper to heat the pool during the winter.

Balance Your Water

Balancing your pool water before closure helps optimize the effectiveness of your winter season pool chemicals.

Properly balancing your pool water now optimizes the efficiency of your winter season pool chemistry. Testing your pool water after cleaning creates a baseline. 

After knowing where your pool chemistry stands you can adjust the pH to 7.3-7.7, alkalinity between 100 and 150 ppm, and calcium hardness around 250 ppm.

Shock your pool 2 days prior to closing with 12.5% liquid shock. Don’t cover your pool if there is still any chlorine in the pool as this could harm the cover.

The chemicals used to balance water levels in pools are called “chlorine sanitizers”.

They are added to the pool water at regular intervals throughout the year to keep it free from bacteria. Chlorine sanitizers come in two forms – tablets and liquid.

Both types dissolve quickly in water, but they react differently. Liquid chlorine sanitizers are more effective than tablets because they are able to penetrate deeper into the water.

Winterizing Chemicals

Closing An Above Ground Pool

Now that you’re ready, it’s time to check out your chemicals. There are many products you can use to make your pool safe.

You should choose what works best for your needs. And, of course, make sure to handle and use them safely.

Winterizing chemicals keep your pool safe from algae growth. Add them to your pool the day before you want to close it.

Make sure they are mixed well. Then, tie the winter tabs securely in place.

Don’t let them touch the pool liner. Run the filter for four hours after applying the winterizing chemicals.

Pool chemicals should be used regularly to maintain the health of your pool.

Adding pool enzymes to your water helps fight off any organic contaminants that may be present. Antifreeze should be used when your pool freezes over.

Winter Pool Algaecides

The most common algae killer is copper sulfate (CuSO4). It works by causing the cells to die off, so it kills all types of algae.

Copper sulfate is available at any pool supply store. If you don’t want to use this chemical, you can try using chlorine bleach.

Chlorine bleach will kill algae but not necessarily all types of algae.

You can find out how much chlorine you are using by checking your pool’s pH level. A low-pH reading indicates that you’re using too much chlorine.

To correct this problem, add more acid or adjust the amount of time you leave the chlorine in the water.

Too much chlorine can cause skin rashes, eye irritation, and breathing problems.


The enzymes will break down any organic material in the water.

This includes leaves, sticks, and other debris from plants growing around the pool.

If this material isn’t removed regularly it can clog the filter and cause algae blooms.

The chemicals used to treat a swimming pool are very dangerous if ingested by children or pets.

They also pose a threat to the environment because they contain toxic substances that leach into our groundwater supply.

In addition, many of these chemicals have been linked to cancer. So, although they’re essential, you have to be very, very careful with them.

Pump Protector

Apply liquid pump protector through the skimmer. Then let the pump run for 10 secs, then shut off the pumps and let it sit for 1 hour.

This will protect your pumps from getting corroded by pool chemicals.

Seal off the skimmer and return to your pool. If your water level rises during the winter, you may be left with an open return and skimmer.

This could cause damage to your pump and other parts of your system.

To prevent this, seal off the return fitting eyeball (the part that connects the return hose to the skimmer) and plug it with a skimmer plug (a rubber or plastic plug).

Also, seal off the skimmer opening with another skimmer plug. Make certain to get the correct size of skimmer plug, as sizes can vary by pool.

You should only lower the water level when you need to clean the filter or drain the pool. Don’t do anything else while lowering the water level.

Never lower the water level more than an inch below the top edge of the skimmer (the part that goes down into the pool).

This could cause damage to your pool walls, liners, and fixtures.

Winter Pillow Cover

Your pool needs a pillow once every year. You don’t need to sacrifice anything from the linen closet.

A pool air pillow protects both the sides of the pool cover (see also ‘How Do You Remove Rain Water Off Your Pool Cover?‘) and the walls of the pool from pressure damage from ice or snow.

Don’t live in a cold climate? A pillow will still make cleaning up tons easier next spring!

Blow up the pillow and put it in the middle of the pool.

Get a pillow that has built in grommets that allows you to secure all four sides to your pool and keeps it perfectly centered.

Make sure you inflate the air pillows only to around half of their capacity.

Otherwise, it could pop mid season, and you’ll have to deal with some really cold water to replace it! Better yet, seal off any seams and valves with duct tapes after you inflate them.

This will keep them as resilient as possible. You need a little extra strength during the cold months!

Winter covers should be secured to pools with heavy objects such as bricks or concrete blocks.

Covering gaps with heavy objects is important because they prevent debris from falling into the pool.

Cover your pool securely. Use cover clips, cable, or a combination of both to secure the cover in place.

For areas with high winds, it is recommended to install a winter cover seal around the cover to prevent wind damage to the cover.

Don’t hang filled plastic bottles from your cover. This could cause tearing of the cover and void any warranty.

It could also put damaging stress on the pool wall.

Ice Equalizer Pillow

To use an ice equalizer, you need to blow it up first. Then put it into the middle of your swimming pool.

You can also tie it to the sides of the pool. This nifty bit of kit reduces ice pressure on the walls of your pool during the colder months.

What Is Algae?

Closing An Above Ground Pool

Algae are a type of plant that grows in water. They use sunlight to make energy. They also produce oxygen.

Algae do not have brains, but they can sense danger. When there is too much light, they stop growing.

If you don’t winterize your pool properly, algae can be a big problem.

Algae needs food to grow. In a swimming pool, there’s plenty of food for them.

There are also lots of contaminants and other stuff floating around in pools.

These things make algae happy. When algae gets too much food, it grows really fast.

This makes it dangerous because it can be harmful to your health.

Swimming pools should be kept clean by regular cleaning. Chlorine levels should be monitored regularly.

When algae blooms, the pool water should be drained and treated with chemicals.

What Problems Can Algae Cause?

Algae is an aquatic plant that grows in water. It is usually green or brownish-green in color.

Algae blooms are caused by too much nitrogen and phosphorus in the water.

These nutrients cause algae to grow quickly and become toxic to other plants and animals.

To prevent this, people should use chlorine to kill off the bacteria that cause algae growth.

Filter Damage

Pool filters need to be cleaned regularly to prevent clogs. Algae grows in pools and causes problems by hiding in hard-to-reach places.

Algae stains pool surfaces and degrades vinyl liners (see also ‘ How To Easily Patch Any Vinyl Pool Liner ‘).

Algae are plants that absorb sunlight and use it to make energy. They also create oxygen by breathing out carbon dioxide.

Chlorine is used to kill algae. When chlorine levels drop low, algae start growing. This causes the pH level of the pool to rise.

Algae are like weeds in your garden because they take up nutrients and resources from other plants you want to grow.

What Types Of Algae Are Here?

Algae are plants that grow in water. There are many different types of algae.

Some are green, some are brown, and others are red or yellow.

All of them need sunlight to survive.

Green Algae

Algae is a type of plant that grows in water. Green algae is often found floating in water.

It reduces water clarity and makes the water look green.

Green algae is found in many different forms. Some varieties are found in spots, while others form sheets.

Yellow Algae

Yellow algae is an annoying problem. It clings to walls, and it can be difficult to get rid of. Pool owners should treat it aggressively.

Small pockets of it may survive treatments on pool toys, floats, or cleaning equipment.

Yellow algae is resistant to normal chlorine concentrations, so it needs to be treated firmly.

Black Algae

Black algae is an annoying strain of algae that grows in pools and tubs.

It appears as dark black or blue-green spots, usually the diameter of a pencil eraser, up to the size of a quarter.

Roots extend into the pool plaster, and if the roots aren’t destroyed, a new head grows back in the same place again.

Black algae of course blooms when there isn’t enough chlorine in the water – and, because of the roots in the pool plaster, can easily come back.

Swimming pools should be cleaned regularly, and continually chlorinated to avoid this problem.

Pink Algae

Pink algae blooms are usually caused by pollution or lack of oxygen.

This bacteria is found in swimming pools. It attaches itself to walls, floors, and equipment.

It does not grow very fast, but it can linger if left unchecked.

Pink algae also needs chlorine to be treated effectively. Pool toys and floats should be thrown away if they can’t be treated.

Ladders and pool lights should be removed for a good scrubbing. Cyanuric acid is an effective chemical to kill pink algae.

How Is Algae Prevented?

Algae blooms occur when there is an imbalance of chemicals in water.

Cyanuric acid is used as a stabilizer or conditioner to prevent algae growth. High pH and low chlorination allow algae to grow.

Cleaning your swimming pool regularly helps prevent algae (see also ‘The 7 Best Pool Vacuum Algae Reviews‘) growth. Brushing your pool also keeps you fit and healthy!


Closing and winterizing your pool is an essential yearly task! Take the time to get it right, and you’ll ensure the longevity of your pool.

Hopefully, this guide has helped you learn how to do it right!

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By Anthony Barnes

Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age