Closing an above-ground pool involves much more than simply lowering the water level partway. You must prepare the water, remove the accessories, protect every pipe from freezing, and leave the pool in a condition that will make opening it in the spring easier. A missed step can result in a split pipe, damaged pump, scaled salt cell, or green water that is difficult to restore.
This guide presents a complete and logical method for closing an above-ground pool in Quebec. It is intended for homeowners who close their own pools, as well as Piscine Hippocampe employees who must recommend the right products and validate the customer's setup. Since installations vary, the manufacturer's manual and the instructions on the products always take priority.
Safety: Turn off the power before disconnecting a pump, salt cell, or heat pump. Never use automotive antifreeze in a pool. If a pipe is inaccessible or the setup seems unusual, have a technician handle it.
Table of contents
When should you close an above-ground pool?
The best time is when the water temperature remains below 12 °C, or about 55 °F. At this temperature, algae and bacteria develop much more slowly. Closing too early, while the water is still warm, increases the risk of finding cloudy or green water in the spring. However, do not wait until the plumbing is exposed to significant freezing.
In the Montreal region, on the South Shore, and in Montérégie, the exact date varies from year to year. Rely on the actual water temperature and frost forecasts rather than a fixed calendar date.
Before you begin: the 8 essential checks
Confirm the pool volume, filter type, and disinfection method: traditional chlorine or salt system.
Identify whether there is a main drain, heat pump, skimmer light, or special plumbing.
Check whether the pool is losing water. Mark the level and observe it for a few days without significant rain; a leak must be repaired before winter.
Treat any green, cloudy, or contaminated water before closing. Closing products do not replace proper corrective treatment.
Remove the leaves, vacuum, and brush the bottom and walls.
Bring a water sample to a store about 48 hours before closing to obtain a complete analysis and the quantities suited to the pool.
Clean the filter before closing so oils, algae, and deposits are not trapped for several months.
Gather the plugs, pool antifreeze, protective foam, Teflon tape, O-ring lubricant, and appropriate tools.
1. Prepare and balance the water
Two days before closing, clean the pool and have the water tested. This analysis makes it possible to adjust the pH, alkalinity, hardness, chlorine, and, if applicable, salt. It can also reveal a problem invisible to a simple test strip, such as a high level of phosphates or metals.
| Parameter | Starting guideline | Why |
|---|---|---|
| pH | Approximately 7.6 to 7.8 at closing | Cold water can become more aggressive; the final target should be confirmed based on the balance. |
| Total alkalinity | Approximately 100 to 120 ppm | It helps stabilize the pH during the winter. |
| Free chlorine | Approximately 1 ppm before the closing treatment | Avoid an uncontrolled excess that could discolor the liner. |
| Water | Clear and algae-free | Problematic water must be corrected before adding the closing kit. |
These values serve as guidelines for the Piscine Hippocampe protocol. The analysis results, pool finish, sanitation system, and product labels determine the final adjustment.
Clean the filter before shutdown
A dirty filter reduces circulation during the application of the final products and leaves contaminants in the equipment. Use a cleaner designed for the filter media, such as Rapid Action Filter Cleanse, following the instructions. Then circulate the water long enough to complete the cleaning before lowering the level.
If your protocol includes a stain and scale prevention product, add it while filtration is still running. The quantity should be selected according to the pool’s actual volume and the label
2. Remove the accessories
- Remove the ladder, steps, and removable accessories. Clean them, let them dry, and store them in a sheltered place.
- Remove the thermometer, toys, floating dispensers, and any object that could strike the liner during the winter.
- Wash the solar cover with a suitable product, dry it completely, and store it in a place protected from rodents.
- Remove the removable lights. A light installed in the skimmer must be disconnected and stored according to the manufacturer’s instructions.
3. Lower the water level without draining the pool
An above-ground pool should never be completely drained for the winter. The water supports the structure and liner. After closing the skimmer intake and stopping the pump, generally lower the level to about 45 cm, or 18 inches, below the skimmer, unless the manufacturer or the technician responsible for your installation specifies otherwise.
You can use the WASTE position on a filter that has one, or a submersible pump. If the water level drops below the skimmer while the filtration pump is running, it may draw in air and run dry. Do not try to maintain the prime with a hose unless your setup allows it and you know how to protect the pump.
Do not: Never let a pump run without water. Slow drainage must also be directed away from the pool, house, and neighboring properties to prevent erosion or seepage.
4. Protect the main drain pipe
The main drain remains underwater; its pipe must therefore be isolated and protected against freezing. The recommended method generally consists of disconnecting the pipe at the designated point near the valve or skimmer, then installing an extension that rises above the maximum water level.
Shut off the circulation and disconnect the pipe at the designated fitting.
Securely attach the extension to the main drain pipe and keep it vertical, above the top of the pool.
Add only biodegradable antifreeze designed for pools, using the quantity and method recommended for the installation.
Insert the specified foam or Ethafoam into the pipe to reduce the amount of water that could freeze.
Seal the extension with a watertight plug and secure it so it cannot tip over during the winter.
Avoid makeshift methods that leave water trapped at a low point or rely on a single poorly supported plug. A suitable extension kit makes the procedure more predictable and easier to check in the spring.
5. Winterize the skimmer and return
Skimmer
Remove the basket and floating door, clean the inside, and install the foam protector designed for your model. This foam helps absorb ice expansion and reduce pressure on the plastic. If your skimmer has a light, remove the module and its transformer according to the manufacturer’s instructions; reinstall the screws to avoid losing them.
Return
Remove the directional eyeball fitting with the appropriate tool. Do not use plumbing pliers, which could mark or crack the part. Depending on the configuration, install a winterizing plug or a short hose to serve as an overflow. This hose must direct autumn rain away from the wall and foundation.
6. Drain and store the pump
Turn off the power at the circuit breaker before handling anything. Disconnect the hoses, remove the drain plugs, completely empty the pump housing, and clean the basket. Inspect the O-rings; clean them and apply only a compatible lubricant if recommended by the manufacturer. Store the pump in a dry place, ideally somewhere it will not be exposed to freezing temperatures.
A pump that still contains a small amount of water can crack when it freezes. Leave the plugs removed during storage and place them in a labeled bag to make opening easier.
7. Winterize the filter
| Filter type | General procedure |
|---|---|
| Sand filter | Remove the pressure gauge, clear sight glass and bottom plug. Drain all the water and set the valve to the Winterize position if it has one. Store the small parts together. |
| Cartridge filter | Remove the pressure gauge, air relief valve and bottom plug. Remove the cartridge, clean it according to the product label, rinse it, let it dry and store it in a dry place. |
Good practice: bring the pump, pressure gauge, salt cell or any questionable parts to a branch for inspection before storage. It is easier to replace a part in the fall than to discover a failure on opening day.
8. Close a saltwater system
A saltwater chlorine generator generally performs less effectively as the water cools. Do not expect it to provide a complete closing treatment. Turn off the power, disconnect the cell and inspect the plates. Clean it only if deposits are present, using a product intended for this purpose such as Pristiva Salt Cell Cleaner, then rinse it thoroughly.
Let the cell dry and store it in a clean, dry, frost-protected place. Install a compatible dummy cell or spacer to close the plumbing without leaving the real cell outside. Piscine Hippocampe's saltwater closing protocol may also include Pristiva Primer, Pristiva Premium Shock and Protect Sticks; quantities depend on the pool volume and test results.
9. Winterize the heat pump
- Turn off power to the heat pump at the circuit breaker.
- Disconnect the water inlet and outlet connections, keeping the O-rings.
- Completely drain the water from the heat exchanger and pipes. Blow through the IN and OUT ports only with a method and pressure compatible with the model.
- Leave the connections in the position indicated by the manufacturer and protect the unit with a cover only if one is recommended for that model.
Freeze damage to a heat pump is costly. If you are not certain that the heat exchanger is completely empty, have the unit checked by a professional.
10. Add the closing products
| System | General protocol |
|---|---|
| Chlorine pool | Shock treatment with Dazzle Ultra Shock, followed by Dazzle Algae Clear 60 algaecide, according to the analysis, volume and labels. |
| Saltwater pool | Pristiva Primer, Pristiva Premium Shock and Protect Sticks according to the recommended protocol for the pool. The cell is removed and stored. |
If the pump can still circulate the water safely, let it run for the time specified for the products. Otherwise, carefully distribute the treatment and brush the pool. The exact dosage should never be copied from another pool: it depends on the volume and the product concentration.
11. Install the winter mesh or cover
A mesh limits the accumulation of leaves and large debris, but it must be installed according to its type. Tension, height, and removal timing are essential to prevent it from damaging the pool.
| Type | Installation and monitoring |
|---|---|
| Permanent mesh | Supported by a cable under the coping and a network of tensioners. It must remain above the water and never pull on the wall. |
| Semi-permanent mesh | May rest on the water temporarily while leaves are falling. It must be removed before heavy freezes and snow accumulation. |
12. Monitor the pool after closing
Closing does not end on the day the mesh is installed. After fall rains, check that the level remains sufficiently below the skimmer and that water drains away from the pool. Also inspect the main drain extension, plugs, mesh, and attachments after strong winds.
During winter, do not try to break ice attached to the cover or walls. Instead, carefully remove excess snow if recommended by the cover manufacturer. During thawing, quickly check the water level and the condition of the equipment.
Quick checklist
Use this list as a reminder when closing the pool.
Closing shopping list
| Category | To be prepared according to the installation |
|---|---|
| Water Treatment | Dazzle or Pristiva kit, shock treatment, algaecide, stain prevention, and Protect Sticks as required by the system. |
| Cleaning | Rapid Action Filter Cleanse, waterline cleaner, brush, deep leaf net, and vacuum accessories. |
| Plumbing | Biodegradable pool antifreeze, Ethafoam, main drain extension, plugs, Teflon tape, and compatible lubricant. |
| Protection | Skimmer foam, salt cell spacer, mesh or cover, and suitable tensioners. |
| Parts | Worn O-rings, pressure gauge, fittings, or plugs identified during the inspection. |
Most common closing errors
Closing while the water is still warm, which encourages algae growth until freezing.
Adding products without testing the water or knowing the pool volume.
Completely draining the above-ground pool and removing the support that the water provides to the structure.
Leaving water in the pump, filter, heat pump, or a low point in the plumbing.
Using automotive antifreeze or mixing chemicals together.
Storing a filter cartridge or salt cell while it is still dirty and wet.
Installing a permanent cover that touches the water or forgetting to remove a semi-permanent cover before freezing.
Failing to monitor the water level after fall rains.
Frequently asked questions
At what temperature should you close an above-ground pool?
Ideally, wait until the water remains below 12 °C, or about 55 °F. This temperature slows algae growth. Still, monitor the forecast so you can finish before the lines freeze severely.
How far should you lower the water?
The standard procedure is to lower the water to about 45 cm, or 18 inches, below the skimmer. The exact level may vary depending on the pool, skimmer type, return line, and manufacturer’s instructions.
Can you completely drain an above-ground pool for the winter?
No. The water supports the liner and structure. Completely draining the pool can cause shifting, wrinkles, or damage from wind and freezing.
Should you add antifreeze to all the lines?
Not automatically. Use only biodegradable antifreeze designed for pools, and only in the lines specified by your installation’s winterization method. Never use automotive antifreeze.
What should you do with the cell of a saltwater system?
Turn off the power, remove the cell, clean it with a compatible product if it has scale buildup, rinse it, and store it in a dry place. Close off the plumbing with a spacer or a suitable dummy cell.
Should you cover a heat pump?
Only if the manufacturer recommends a compatible cover. The essential step is to turn off the power and completely drain the heat exchanger and fittings to prevent freeze damage.
Is water testing really useful before closing?
Yes. It helps correct the parameters that affect corrosion, scale, stains, and sanitizer effectiveness. Bring in a sample about 48 hours before closing.
Can you leave a leaf cover on all winter?
A properly supported permanent cover can remain in place as long as it stays above the water. A semi-permanent cover that rests on the water should be removed before heavy freezes and snow.
