Figuring out exactly how to winterize an above ground saltwater pool might seem like a bit of a headache, especially with that extra salt cell involved, but getting it right saves you a massive cleanup job when the weather warms back up. If you've spent the whole summer enjoying that soft, silky water, the last thing you want is to open the cover in May and find a swampy mess or a cracked pump. Saltwater systems are great for low-maintenance swimming, but they do require a few specific steps when the temperature starts to drop.
The goal here isn't just to keep the water from turning green; it's to protect your equipment from the brutal reality of freezing temperatures. Ice is incredibly strong, and if it expands inside your pipes or your salt cell, you're looking at an expensive repair bill come spring. Let's walk through the process of putting your pool to bed for the winter so you can rest easy while the snow flies.
Get your water chemistry dialed in first
Before you even think about pulling out the winter cover, you need to make sure your water is balanced. This is probably the most important part of the whole process. If your chemistry is off when you close the pool, those issues are just going to sit there and fester for months.
Start by testing your water about a week before you plan to close. You're looking at the usual suspects: pH, alkalinity, and calcium hardness. You want your pH between 7.2 and 7.6 and your alkalinity between 80 and 120 ppm. Why does this matter for a saltwater pool? Well, salt can naturally cause the pH to drift upward, and high pH water sitting in a stagnant pool all winter is a recipe for scale buildup on your liner and equipment.
Don't forget the calcium hardness, either. If your water is too soft, it'll actually try to "eat" the metal components in your pool to get the minerals it needs. Keep that calcium between 200 and 400 ppm. Once everything is balanced, give the pool a final "shock" with liquid chlorine or a non-chlorine oxidizer. Even though your salt cell makes chlorine, a manual shock ensures every bit of organic matter is dead before the cover goes on.
Clean the pool like you mean it
It's tempting to skip the deep clean since "no one is going to see it," but any leaves, dirt, or bugs left behind will break down and consume your winter chemicals. This leads to that dreaded "green opening" in the spring.
Grab your vacuum and get every last bit of debris off the floor. Brush the walls and the floor really well to knock loose any invisible algae spores that might be clinging to the liner. If you've got a lot of trees nearby, you might even want to do this twice. A clean pool stays clear longer, and it makes the chemical treatment much more effective.
Dealing with the salt cell and generator
This is where the process differs from a standard chlorine pool. Your salt chlorine generator is a sensitive—and expensive—piece of equipment. Most salt cells stop working effectively once the water temperature drops below 50 or 60 degrees anyway, so there's no point in leaving it running.
Cleaning the cell
Once you've turned off the power, remove the salt cell from the plumbing. Take a look inside at the metal plates. If you see white, crusty deposits, that's calcium buildup. You'll want to use a mild acid wash (usually a mix of water and muriatic acid, or a store-bought cell cleaner) to dissolve those deposits. Just be careful with the acid—always add acid to water, never the other way around.
Indoor storage
After the cell is clean and dry, don't just leave it outside. Most manufacturers recommend storing the salt cell indoors in a climate-controlled area. The freezing and thawing cycle can damage the sensors and the plates inside. The same goes for the control box if it's easy to remove, though most people just leave the box mounted and make sure the power is completely disconnected.
Lower the water level and drain the lines
You can't leave water in your plumbing during a freeze. As water turns to ice, it expands by about 9%, which is more than enough to split a PVC pipe or crack a plastic housing.
For an above ground pool, you usually want to drain the water to about 4 to 6 inches below the skimmer. This prevents water from getting into the skimmer mouth and freezing. If you use a "skimmer plate" or a winterizing plug, you might not have to drain it quite as far, but lowering the level is the safest bet for most people.
Once the water is down, disconnect all your hoses. If your pool has hard plumbing, use a shop vac to blow the air through the lines until you see bubbles coming out of the returns, then plug them up with rubber winter expansion plugs. You want those lines bone-dry.
Winterizing the pump and filter
Now it's time to handle the heavy lifting equipment. Your pump and filter need to be completely drained of water.
- The Pump: Remove the drain plugs from the bottom of the pump housing. Shake it a little to make sure all the water is out. It's a great idea to bring the pump into the garage or basement for the winter to keep the motor dry.
- The Filter: If you have a sand filter, set the multi-port valve to "Winterize" and pull the drain plug at the bottom. Be patient; it takes a while for a big sand tank to drain. If you have a DE or cartridge filter, take the internal elements out, clean them thoroughly, and store them inside.
Pro tip: Put all your drain plugs and small parts in the pump basket and put the lid back on. You'll know exactly where they are next year!
The air pillow and the cover
Above ground pools face a unique challenge: the "ice squeeze." When the top layer of water freezes, it pushes outward against the pool walls. If there's nowhere for that pressure to go, it can actually buckle the steel walls of your pool.
This is where the air pillow (or ice compensator) comes in. Blow it up to about 60-70% capacity—don't fill it all the way or it'll pop—and float it in the center of the pool. When the ice expands, it will crush the pillow instead of pushing against your pool walls.
Finally, pull your winter cover over the pool. Make sure it's centered and that it sits flat on the surface of the water and the air pillow. Tighten the cable and winch until the cover is snug against the side of the pool. If you live in a really windy area, you can use "cover clips" or even plastic wrap around the top edge to keep the wind from getting underneath and flapping the cover around.
Wrapping it up
Once the cover is on, you're mostly done, but don't just forget about it until April. Periodically check the cover to make sure too much water or snow isn't weighing it down. If you get a massive puddle on top, use a small cover pump to drain it off. If the weight gets too heavy, it can actually pull the pool walls inward or snap the cables.
Knowing how to winterize an above ground saltwater pool might take an afternoon of work, but it's the best insurance policy you can have for your backyard oasis. Take care of that salt cell, keep the water level right, and you'll be rewarded with a much easier opening day when the sun finally comes back out.