Most people close their pools when the kids go back to school or by the end of September. When temperatures stay below 65°F (18°C) during the daytime (off-season) and frost at night, it is time to close. NOTE: Closing too early will allow algae to grow and cause a troublesome opening in the Spring.
Why? Algae needs sunlight and heat to thrive. Cold temps help keep your water clear of infestation. As a bonus, leaving your pool open longer with cold weather allows the opportunity to clean, test, and balance your pool before closing.
Test the water yourself with test strips or liquid. If there is a SERIOUS concern then take a water sample to your local pool store and have them test it for you.
pH should between 7.2 and 7.6, and alkalinity between 100 ppm and 150 ppm. Calcium hardness range from 175 ppm to 225 ppm. Chlorine between 1 ppm and 3 ppm. If you use a different sanitizer, just make sure it’s at the proper level for whatever you’re using. Since you won’t be adjusting the water balance during the offseason, it’s better to be on the high side of these ranges when you close your pool because they’ll naturally decrease over time.
Increase alkalinity by increasing the base using sodium bicarbonate to your pool water. Reduce with muriatic acid. Adjust alkalinity before pH because it has an impact on pH readings. Ensure that pH targets are met. Raising or lowering the pH is using the same chemicals as adjusting the alkalinity. Raise the pH with soda and lower with acid.
Hard water deposits calcium in your pool and plumbing, forming a build-up over time. Too-soft water can also corrode metal.
If your water’s too hard, add salt. Too soft, add calcium chloride.
When using calcium hypochlorite or trichlor pucks, use fast-acting pucks that dissolve within 24 hours. Alternatively, use up your supply of liquid chlorine (sodium hypochlorite) as to not have to store it over winter. Using triple the normal amount will have no negative effect.
Add C-Poolandspa or an algaecide to your pool just before closing it to keep algae from invading over the winter.
Also add (optional) a clarifying enzyme treatment ( such as C-Spa Non-foaming Enzymes) to further reduce algae growth, liner stains, and contaminant build-up. Add a few capfuls to the water, where they work all winter to help you greet spring with a clear pool. If you’ve struggled with a green, murky pool at the opening in the past, or want to avoid one in the future, using C-Poolandspa and C-Spa can help immensely.
It is the final cleaning of the season. Vacuum the entire pool, brush down the walls, and skim the surface. Keep the filter running to clarify the water. Brush out any algae from the vinyl seams. A little prep now will save you from some potentially nasty surprises when you open your pool next spring. A clean pool makes it easier to properly balance your water. It also ensures nothing is left behind to feed algae or mold that might develop over winter.
4. Clear and Store Lines
Water trapped in your pool lines can damage the lines by ice expansion. Even if winters are mild in your area, clearing, removing, and storing the lines will make for easier setup next spring. Simply disconnect the lines, allow all the water to run out, let them air dry, then store them in a dry place out of direct sunlight. HINT: Letting them dry is crucial to prevent mold in them in the Spring.
5. Protect Skimmer
Remove the skimmer basket and store it somewhere safe and dry for the winter. There is an option to cover your skimmer for the season or not. A winter skimmer cover is a plate that covers the entire skimmer, sealing out the elements. If you use one of these, you won’t have to drain your pool below the skimmer line. This a time and maintenance saving. If you choose not to cover your skimmer, make sure water can drain out if it rains. Keep the bottom of the skimmer free and clear—don’t plug it up or the freezing water will crack it.
6. Winterize The Filter and Pump
The Pump: Completely remove all drain plugs to drain and remove the pool pump, chlorinator (if you have one), and all the hoses. Store all the drain plugs (including the ones from the filter) in the pump basket so that you keep them all together and you won’t have to go hunting for them in the spring. Keep the pump, chlorinator, and hoses indoors to prolong their lives.
The Filter: The method you use for winterizing your above ground pool will depend on which type of filter you have.
Sand: Set your multiport valve to “Winterize,” and remove the drain plug at the bottom to allow the filter to drain completely. If your multiport valve has a bleeder valve and a sight glass, remove those too, and store them in the pump basket for easy retrieval next season.
Bring your filter indoors for winter storage. If the weight of the sand makes this too difficult, you can leave it outside if you remove all the drain plugs. With the plugs removed, freezing water or condensation that builds up inside the filter tank won’t crack it.
Diatomaceous Earth (D.E.): Drain it, then rinse off the grids (or fingers) with a hose to remove excess D.E. Leave the valves open.
Cartridge Drain it, then rinse off the cartridge with a hose. Leave the valves open, and store the cartridge indoors for the winter.
Note: Moving your hardware indoors after you disconnect it really is the best option. It extends your gear’s useful life and protects it from damage. Protect your investment and bring your filter, pump, chlorinator, heater, and any other equipment in from the cold.
SALTWATER: If your pool uses a saltwater system, switch the chlorine generator to the “winter” setting, if it has one. If it doesn’t, most chlorine generators have a removable electrolytic cell you can access by unscrewing the end caps. Remove the cell, or your entire salt system if you prefer, and store it inside for the winter.
Note: Take a few moments to clean the cell before storing it. It’ll prolong its life and help reduce the risk of hardware problems when it’s time to reopen your pool.
Gather up your pool ladder, floaters, toys, and any other accessories you may have. Leaving them in the pool can damage the items or, even worse, your pool. They could puncture the lining or start to rust. Corroded metal can contaminate your water and cause serious hardware problems. Gather up all your accessories, then give them a good cleaning and let them dry. Then store them in a clean, dry place, away from direct sunlight, until spring.
8. Lower Water
Drain any water when winterizing to protect your skimmer during the winter. If you’re concerned about freezing and cracking and don’t use a winter skimmer cover plate, then you should drain the water level below the skimmer and returns.
If you do use a winter skimmer plate, remove the hose from your skimmer (so it can drain properly), and install the plate, and you won’t have to drain your pool. Keeping the water level at its normal level is said to be better for your winter cover because draining the water below the return lines can put added pressure on your cover when rainwater and snow collect on top. You’ll need to keep draining water off the cover with a pump or siphon to protect it from damage.
Important: Never drain an above ground pool completely when winterizing. Your vinyl liner can dry out, shortening its life considerably.
9. Air Pillow
In cold climates, placing an air pillow (compensates for the pressure of the snow and ice on top of the cover) under the cover protects the walls of your pool from damage. If you close and cover your pool, use it to keep water and debris off to the side of the pool for an easy spring clean-up.
10. Pool Cover
Place the pool cover over your pool—and the air pillow—and secure with cable and/or clips. Sometimes, more really is more. A combination of winter cover clips and a cable and winch will ensure a snug fit and give you greater peace of mind. If your pool has a walk-around deck, you can also add water bags to help secure your cover. Bricks, stones, or anything else may damage your liner if it were to fall into the pool. Keep the cover dry.