How to Winterize a Saltwater Pool With a Variable-Speed Pump: Step-by-Step

Closing a regular chlorine pool is already a to-do list. Closing a saltwater pool with a variable-speed pump can feel like you need a whole separate checklist on top of it – because you kind of do. The salt cell, the pump’s programmed schedules, and the chemistry targets all behave differently than a standard setup, and missing one step can turn a $150 closing into a $600 repair bill come spring.

The short answer is this: winterizing a saltwater pool with a variable-speed pump means balancing water chemistry to specific targets, removing and storing the salt cell, blowing out and plugging all lines, disabling every scheduled run on the pump, then covering the pool. This article walks through each of those steps in order, with exact numbers, so nothing slips through the cracks. If you want a broader overview of the full inground closing process, Liquid Luxury Pools has a solid general reference alongside what we cover here.

Step 1: Balance the Water Chemistry First

Do this at least 24 hours before you plan to close. Water that sits under a cover all winter at the wrong chemistry will stain, scale, or corrode – and you will deal with the fallout in spring when you want to be swimming, not scrubbing.

• pH: Target 7.2 to 7.4. Lower than normal operating range, because pH drifts up under a closed cover and you want to start on the lower end.
• Total Alkalinity: 80 to 120 ppm. Alkalinity buffers the pH during the months of dormancy.
• Calcium Hardness: 200 to 400 ppm. Too low and the water pulls calcium from your plaster or tile grout. Too high and you get scale on the salt cell and walls.
• Cyanuric Acid (CYA): 60 to 80 ppm. The salt cell will not be running, so you want some stabilizer present to protect any residual chlorine from UV during the last few sunny days before the cover goes on.
• Salt Level: Keep it in the normal operating range, 2700 to 3200 ppm. You do not need to dilute it down – the salt will still be there in the spring with minimal drift.

Once chemistry is balanced, shock the pool with a non-stabilized chlorine shock dosed to raise free chlorine to 10 to 12 ppm. Let the pump circulate for at least 2 hours – or run it overnight – before moving on. Do not add the shock while the salt chlorinator is still generating, or you will be working against the cell.

Step 2: Turn Off and Remove the Salt Chlorinator Cell

This is the step that trips up people who have only closed chlorine pools before. The salt cell is not plumbing – it is a piece of electronics with titanium plates inside, and freeze-thaw cycles will crack the housing or damage the plates if it stays installed. Remove it before temperatures drop near freezing.

Turn off the chlorinator at the control panel first, then unplug the cell from the power cord. Loosen the unions on either side of the cell (most are hand-tight), pull the cell out, and plug each union port temporarily so debris does not fall into the plumbing while you work. Inspect the cell plates: if you see heavy white scaling, a short acid wash before storage (one part muriatic acid to ten parts water, soaked for 5 minutes, then rinsed) will extend its life. Store the cell indoors – a clean bucket with a little water in the bottom keeps the plates from drying out and cracking.

As a side note, if you have been doing your pre-closing brushing with whatever brush was on the shelf, saltwater pools actually do better with specific bristle materials. The best pool brushes for saltwater pools use nylon or stainless steel rather than plain stainless, which can scratch certain surfaces.

Step 3: Run the Variable-Speed Pump Through Its Pre-Close Sequence

Variable-speed pumps are more efficient and more capable than single-speed models, but they also have more settings to undo before winter. The concern is leaving an active schedule that tries to run the pump after lines are blown out and plugged. A dry-running pump damages its seal within minutes. For a deeper look at how these pumps interact with salt systems year-round, Swimming Pool Steve’s breakdown of variable-speed pumps with salt systems is worth reading.

Here is what to do with the pump before closing:

1. Log into the pump’s control panel or app and disable all scheduled programs. Do not just pause them – delete or turn them off entirely so a power cycle does not re-enable them.
2. Run the pump at its highest speed (typically 3450 RPM) for 30 minutes to circulate the shock dose evenly and flush any settled debris toward the skimmers.
3. Drop the pump to a medium speed (around 2000 RPM) for the water-lowering and backwashing steps below, then shut it down completely when lines are ready to blow out.
4. Once lines are blown and plugged, power off the pump at the panel, then cut the breaker at the electrical panel. Do not leave it on standby.

Wondering how long to run the pump on closing day before you shut everything down? A full turnover – circulating the total pool volume once – is the minimum. Running it for one complete turnover cycle after adding winter chemicals is the standard recommendation before the final shutdown.

Step 4: Lower the Water Level and Clean the Pool

Lower the water to 4 to 6 inches below the lowest return jet for a mesh cover, or 1 inch below the skimmer mouth for a solid cover. This protects skimmer bodies and return fittings from expanding ice. Use the pump on a medium speed setting to drain, or a submersible pump if you prefer to keep the circulation system dry during this step.

Vacuum and brush the walls and floor before covering. Any organic material left on the walls – algae, leaves, oily residue – will have all winter to bond to the plaster or liner. This is also a good moment to clean the pump basket and skimmer baskets, and to backwash or rinse the filter one last time.

Step 5: Blow Out and Plug the Lines

This is the step that actually prevents cracked pipes. Use a shop vac on the exhaust setting, or a small air compressor set below 30 PSI, to blow air through each line until bubbles stop coming out of the corresponding return or skimmer. Work from the equipment pad outward.

• Skimmer lines: Blow from the skimmer toward the pump, then plug the skimmer port with an expansion plug (also called a Gizzmo or winter plug).
• Return lines: Blow from the pad toward the pool, then plug each return fitting with a return line plug. Tighten them firmly but do not overtighten – hairline cracks start from overtightened plastic fittings.
• Heater bypass: If your system has a heater, bypass it before blowing lines so you do not push water into the heat exchanger. Then drain the heater separately per the manufacturer’s manual.

After blowing lines, add 1 to 2 quarts of pool-grade propylene glycol antifreeze per line as an extra precaution, particularly on lines you cannot guarantee are fully clear of water. Never use automotive antifreeze – ethylene glycol is toxic to pets and will contaminate the pool water in spring. AquaDoc’s winter closing chemical kit includes a compatible closing algaecide for this stage, for pool owners who want to treat lines and the pool surface in one pass.

Step 6: Service the Filter and Equipment Pad

Drain the pump housing completely by opening the drain plugs on the bottom. Store the drain plugs somewhere you will actually find them in spring – many owners tape them to the pump housing or put them in a zip-lock bag inside the pump basket. Drain the filter tank. For a sand filter, turn the multiport valve to the “winterize” position if it has one, or pull the drain plug and leave it out. For a cartridge filter, remove, clean, and store the cartridge element indoors.

Disconnect the variable-speed pump’s bonding wire if your local code or manufacturer requires it during off-season storage, and cover or wrap exposed equipment pad components if you are in a climate with heavy snow or ice accumulation.

Step 7: Install the Winter Cover

Install the cover according to its type – water bags and a solid cover, or anchors and a safety cover. Make sure the cover is tight enough that wind cannot get underneath and billow it, but leave enough slack that it will not pull tight under the weight of rain or snow. For solid covers, have a submersible pump ready to remove standing water after storms so the cover does not sink into the pool.

Frequently Asked Questions

Do I need to remove the salt cell when closing a saltwater pool for winter?

Yes, remove the salt cell before closing. Cold temperatures and freeze-thaw cycles can crack the cell housing and damage the titanium plates. Store it indoors in a bucket with a small amount of clean water, or in its original packaging, away from freezing temperatures.

What should salt level be when closing a saltwater pool?

Leave salt levels in the normal operating range, between 2700 and 3200 ppm, when closing. You do not need to dilute or remove salt before winter – the existing level will carry over to spring with minimal drift, and the salt itself does not freeze or degrade over the off-season.

How do I winterize a variable-speed pump on an inground pool?

After balancing chemistry and blowing out lines, disable all scheduled programs through the pump’s control panel or app, run a final full-speed circulation cycle, then shut off the pump and cut the breaker at the electrical panel. Do not leave any low-speed schedules active, as water sitting in partially drained or plugged lines can still freeze if the pump unexpectedly runs.

How much antifreeze does a saltwater pool need for winterization?

A typical inground pool with two skimmer lines and two return lines needs roughly 1 to 2 quarts of pool-grade propylene glycol antifreeze per line after blowing out the pipes. Never use automotive ethylene glycol antifreeze in pool plumbing – it is toxic and will contaminate your water in spring.

Can I leave a variable-speed pump running at low speed all winter instead of closing the pool?

In climates where temperatures rarely drop below 32 F, some owners run a variable-speed pump continuously at 1000 to 1500 RPM to prevent freezing. In climates with sustained hard freezes, this is not a reliable substitute for a full closing – a power outage lasting even a few hours can freeze and crack plumbing that was depending on continuous water movement.

Closing a saltwater pool with a variable-speed pump comes down to three things no standard closing covers: getting the salt cell out and stored safely, clearing all scheduled pump programs so nothing runs on empty lines, and treating your chemistry targets slightly lower than summer normal so the water stays balanced under a sealed cover for months. Do those three things right, and spring startup is genuinely easy.