If you’ve ever stood over a skimmer in late October with a compressor humming and frost nipping your knuckles, you already know: a good pool closing is equal parts technique and stubborn patience. The water in your lines does not care about your timeline. It will expand, crack, and quietly ruin your spring if you leave even a spoonful where it shouldn’t be. That is why blow‑out technique matters more than any single gizmo or brand of gizmo. Whether you handle your own inground pool closing or hire a pool closing service, the result should be the same. Dry lines, protected equipment, balanced water, and a cover that stays put through the nastiest freeze-thaw cycle your climate can throw at it.
I’ve winterized vinyl, fiberglass, and gunite pools through prairie cold snaps and shoulder‑season rains. Winnipeg pool closing season, for instance, doesn’t offer much margin for error. The first deep freeze arrives fast, and a missed return fitting can cost a wall section or a heater header. The fundamentals below work across regions and pool types, and they’ll help you keep your closing ritual efficient, repeatable, and calm.
Why blowing out lines is the make‑or‑break step
A clean pool with perfect chemistry will still give you grief if an inch of water remains in a line elbow or trapped behind a check valve. Water expands roughly 9 percent by volume as it freezes. In confined plastic, that expansion wins every fight. Lines split, couplers crack, and pump housings spider with hairline fractures you won’t see until spring priming fails. The blow‑out, done right, removes liquid water from vulnerable spots and replaces it with stable air and a cushion of non‑toxic pool antifreeze where needed.
People often ask whether antifreeze alone can replace a proper blow‑out. It cannot. Antifreeze is insurance, not the foundation. If you rely on it to displace pooled water, you’ll get dilution and channels of freeze in uneven low points. You need air to move water first, then antifreeze to occupy what air can’t reliably protect.
The gear that actually helps
Pool techs love toys, but for blow‑outs, simple wins. A good air source, thoughtful plugs, and trustworthy valves do the heavy lifting. A mid‑sized leaf blower won’t cut it. You need directed pressure that holds steady.
- What I use when closing an inground pool: a 3 hp pool line blower or a shop air compressor regulated to 20 to 30 psi, winterizing plugs with o‑rings and Schrader valves for returns, Gizmo‑style or threaded expansion devices for skimmers, and a few gallons of pool‑grade propylene glycol antifreeze. That pressure range, checked at the manifold or tee, gives you push without shredding gaskets. On fragile older plumbing, I stay closer to 15 to 20 psi and give it time.
In tight yards or where neighbors bristle at noise, a quiet oilless compressor with a 6 to 8 gallon tank is civilized and effective. If you run a heater, you’ll want a union wrench and a habit of checking for water inside the exchanger header, even after you think it’s dry.
Start with water level and chemistry, not the blower
A top‑tier blow‑out doesn’t fix poor prep. Get your water balanced and sanitized, then lower it to the right height. For vinyl and fiberglass, I usually drop to just below the returns. On gunite with tile bands, I go a hair lower to keep freeze ridges off the grout line. Skimmers don’t need to be bone dry by drainage alone because you’ll deal with them during the blow‑out, but take the load off them.
Adjust pH to the 7.4 to 7.6 pocket, bring alkalinity into the 90 to 120 range, and target calcium hardness appropriate to your surface. For plaster, I’d rather close at 250 to 300 ppm than risk leaching. Add a broad‑spectrum algaecide a day or two before the closing. If you use a winter enzyme product, dose it after the blow‑out and before the cover goes on. Chlorine should not be sky‑high, especially under a solid cover, or you’ll fade liners and shorten the life of your safety cover stitching.
The anatomy of a smooth blow‑out
Every pool is a little different. Return sets vary, multiport valves hide sneaky water traps, and raised spas introduce check valves that laugh at blunt‑force air. The sequence below keeps flow predictable and avoids backpressure surprises.
Open the equipment pad. Remove baskets, lids, and drain plugs from the pump, filter, and heater. Save every plug in a bucket so nothing goes missing in the mulch. Spin your multiport to recirculate if that’s an option, or to waste if you don’t have a bypass. You want a straight path from pump to returns without forcing air through sand or cartridges. If you can isolate branches with valves, even better. Close what you don’t want to feed yet.
Hook your air source into the pump’s hair‑and‑lint strainer port or into a winterizing manifold connected to the return line. If you use the pump lid opening, make sure the pump basket area is dry so you’re not atomizing leftover water. I like to briefly bump air at low pressure first to listen for leaks and hissing. A steady hiss at a union means a loose o‑ring, not an invisible crack. Tighten before you proceed.
Start with the returns. Bring pressure up gradually. You’ll hear gurgles through the pool as water lifts and spits. As each return blows steady air with no mist, plug it with a rubber or threaded plug. If your plug has a Schrader valve, you can maintain a gentle back‑pressure to keep the line dry while you move to the next fitting. On pools with three or more returns, the last one sometimes burps for longer because you’re pushing water through multiple tees. Be patient rather than cranking pressure. I’ve seen more damage from hurry than from weather.
If your pool has a dedicated cleaner line, isolate it and blow it on its own. These runs are often long and prone to low spots. Sometimes I reverse blow them, connecting at the wall fitting and allowing water to exit at the pad, especially if a check valve near the pad is stubborn. pool closing Keep an eye on the gauge and never exceed the pipe’s comfort zone.
Move to water features. Deck jets, laminars, sheers, and bubblers each have their personality. Jets tend to clear quickly. Sheers, especially with long horizontal headers, hold pockets at the ends. Lift the outer edges with a hand if needed to encourage drainage. On bubbler manifolds within a sun shelf, blow from the pad side and then remove caps at each bubbler to let water escape. Replace caps snugly after the line dries.
Skimmers come next. If you have two skimmers tied to a common line, blow from the pad until both wells churn. Once they blow clean air, plug each throat at the pool wall with a Gizmo or threaded expansion device. This absorbs ice expansion in the well. I also pour a pint or two of pool antifreeze down each skimmer after plugging the throat. Not to displace water, simply to protect the line beyond the throat where air might not perfectly cushion every elbow. Some techs place a cut section of foam rope or a half‑filled plastic bottle in the skimmer well for added buffer. Old school, still effective.
Main drains are last, and they require a little intuition. Most inground main drains loop back to the pad with a tee. You will not empty the main drain pot, and you do not need to. The goal is to displace water from the line up to the pool floor and trap an air column. With the main drain valve open, send air until you see a robust boil at the main drain cover. Keep it boiling for 15 to 30 seconds, then close the valve at the pad while air is still flowing. That seals the line with air. If your pad valves don’t hold air well, a winterizing plug at an accessible union can help, but in most setups the pad valve is sufficient.
Heaters, filters, and pumps: the quiet troublemakers
Heaters hide water. Even after a blow‑out, heat exchangers can hold pockets if the unit sits lower than the rest of the pad. Pull the drain plugs on the heater header and let gravity work. I like to tilt the heater a touch by nudging the front up on a scrap of composite shim for a minute. If half a cup dribbles out of a stubborn port after that, you just saved yourself a split tube.
For sand filters, rotate the multiport through each position while the system is depressurized to evacuate trapped water from the spider gasket cavity. Drain the tank completely. On a large 300‑ to 400‑pound sand unit, leave the drain cap off for winter. For cartridge filters, remove the cartridges, rinse, swimandspas.ca pool closing near me and store them indoors if you have space. Leave the body drained and the band clamp loosish so a freeze doesn’t crush anything. On DE filters, rinse grids thoroughly. Those grids get brittle in the cold when encrusted with DE.
Pumps are simple. Remove the drain plugs, crack the lid, and leave the housing open. Store the plugs in the pump basket. If your area is windy, tuck the lid nearby rather than leaving it perched on the housing. Pump lids can skate down a yard like pucks once gusts pick up.
Antifreeze, used wisely
In moderate climates where the frost line barely grazes pool plumbing depth, a meticulous blow‑out can be enough without antifreeze. In colder zones, or where the pad sits at or below the frost line, I consider antifreeze a cheap ally. It is not an excuse for a lazy blow‑out. After you purge returns and skimmers, feed one to two quarts of pool‑grade propylene glycol into each line you worry about, usually via the pad side or through the skimmer with the throat plugged. On long or low‑slope lines, three to four quarts provides extra comfort. Never use automotive antifreeze. Ethylene glycol is toxic, messy, and not meant for pool systems.
A quick sanity check helps. If you add antifreeze at the pad and see pink trickling out of a return you supposedly plugged, your plug is not seated. Better to discover it now than after the first freeze.
Raised spas and tricky hydraulics
Raised spas and spillways complicate things because of check valves and elevation changes. Air prefers to run uphill, and check valves prefer to block your plan. If the spa returns are higher than the pool water line, blow them from the spa side when possible. Open unions near check valves to bypass them. You may need to isolate each spa jet bank to get a clean purge. Once blown, plug jets at the spa wall if they are threaded, then add antifreeze from the pad to cover elbows that sit below grade. Spa air lines, if you have an air blower, also need purging. Reverse blowing through the air manifold, with the blower disconnected, prevents water from sitting in the loop.
Spillways should be left dry underneath. If yours has an internal trough, inspect it with a flashlight to confirm no standing water. A little antifreeze along the trough is harmless, but most spillways drain once you purge.
Above ground pool closing is a different beast
Above ground pools can be deceptively simple. The lines are shorter, often exposed, and more forgiving to purge. They are also more vulnerable to wind and cover mishaps. When I handle an above ground pool closing service, I still blow out the return and skimmer lines, but the plug selection changes. Threaded return plugs and a winter skimmer plate make life easier. Because runs are short, a small compressor at 15 to 20 psi clears them quickly. I remove and store hoses indoors. I also recommend a little antifreeze in the skimmer and return lines if the equipment is set low or the yard collects cold air.
The cover matters just as much. In windy corridors, a cable and winch on the perimeter plus a few well‑placed cover clips can save a January rescue mission. Ice jackets the walls in a cold snap, and a ripped cover draped inside the pool becomes a fishing expedition in spring.
The Winnipeg factor, and other cold‑climate lessons
If you’ve searched for pool closing near me in a place like Winnipeg, you know the stakes are higher. Cold arrives early and stays late. In these regions, inground pool closing demands a hard stop date well before the first serious freeze. Start watching night lows back in September. Pick a calm day. Wind steals heat from wet hands and whips plugs out of grasp just when you need finesse.
I rely on lower air pressures and longer dry‑out time in deep cold regions. I favor threaded plugs with o‑rings over friction rubber on older return fittings. I put a bead of silicone lube on plug threads so I don’t gall the fitting. On long runs across a frozen yard, I add an extra quart of antifreeze and a mental note of any shallow buried sections.
Heaters hate deep cold. I go out of my way to confirm the heater header is dry by removing unions and tipping as needed. For exposed pads that suffer drifting snow, a breathable equipment cover helps. Don’t wrap pumps and heaters in plastic. Condensation under plastic freezes and thaws against metal and electronics, which does more harm than a dusting of snow.
When to bring in an inground pool closing service
There’s pride in doing your own closing. There is also wisdom in asking for help when your plumbing is complex or your schedule is stacked against a good weather window. If your pool includes a raised spa, multiple water features, and automation with check valves all over, a professional inground pool closing service can be the cheapest part of your season. The tech will know which unions to crack, which valves to set where, and how to pressure test a suspicious line. They’ll also carry fittings you didn’t realize you needed. If you live in a short season region where Winnipeg pool closing happens in a rush, the service calendar is tight. Book early so you don’t get caught with frozen water in an elbow while you wait for an opening.
For simpler layouts, DIY works well if you’re patient. Keep a notebook with last year’s plug sizes and sequence. That tiny habit trims an hour off your day.
The two lists you’ll actually use
Winterizing a pool throws a lot of details at you. The short check below keeps your sequence clean without turning your day into a scavenger hunt.
Essentials to stage before you start:
- Air source with regulator, winterizing plugs and Gizmos, o‑ring lube, pool antifreeze, union wrench, and teflon tape Water test kit and closing chemicals, including algaecide and enzyme if you use it Skimmer baskets, pump basket, and all equipment drain plugs gathered in a labeled bucket for reassembly in spring Safety cover hardware, anchors cleared of debris, and a long‑handled hex key or drill bit for anchor adjustment Towels, gloves, and a headlamp if you’re flirting with dusk
A concise blow‑out sequence that avoids rework:
- Lower water to just below returns, balance chemistry, remove ladders and accessories Open pad, remove equipment plugs and drain water, set valves to isolate returns first Connect air at the pump or manifold, blow and plug returns one by one, then water features and cleaner line Purge skimmers, install Gizmos, add a pint or two of antifreeze per skimmer, then establish and trap an air lock on the main drain Dry heater, filter, and pump, add antifreeze to long or low‑slope lines, install cover, and secure perimeter
Mistakes that don’t look like mistakes at the time
Cranking pressure to 50 psi because the last return won’t clear is a classic way to blow a weak union. Step back instead. Is a valve half‑closed upstream? Is there a check valve stealing your flow? Sometimes reversing direction at a union clears the holdout with half the pressure.
Forgetting to move the multiport off filter mode before introducing air sends air through media you just rinsed. Sand kicks up, fine DE puffs out, and your pad turns into a dust bowl. Set recirculate or waste first, and you’ll keep the mess out of the filter belly.
Plugging returns as soon as they sputter gives a false sense of security. Wait until the spray turns to a consistent, dry airflow. That extra minute saves a surprise freeze in a low elbow.
Leaving fittings bone dry but the skimmer wells full invites a freeze jacket. A Gizmo or expansion device isn’t optional where winters bite. It’s the cheap sacrificial hero that prevents a cracked skimmer body.
Skipping a final walk around the cover leaves you with a flapping panel or a sharp anchor ready to chew the fabric all winter. Tension should be even, not guitar‑string tight on one side and slack on the other. On safety covers, I aim for springs compressed about one third to one half, which keeps the fabric taut without overloading the anchors.
A word on automation and smart valves
Automation brains make life easier in July, then complicate closings in October. Put the system in service mode so nothing tries to move while you work. If your actuators sit across three‑way valves, verify the handle positions match the actuator orientation. Otherwise, you’ll be blowing into a closed pathway while thinking a valve is open. On older systems, unplugging actuators and moving valves by hand during the blow‑out avoids confusion. Label everything with painter’s tape before you disconnect. In spring you’ll thank your fall self.
Regional searches, real decisions
If you’re hunting for pool closing near me because your weekends are spoken for, ask a few pointed questions before you book:
- What pressure do you use for line blow‑outs, and do you regulate it? How do you handle raised spas or check valves? Do you add antifreeze, and if so, where and how much? Do you photograph plug placements and anchor settings for spring reference? Can you schedule around a calm day rather than the first available slot?
A competent crew will answer in specifics, not mottos. For homeowners in Manitoba, a Winnipeg pool closing provider who works winter after winter in that climate has a feel for the little local quirks, like wind patterns that lift certain covers or pads that ice over from gutter overflow. The same goes in lake‑effect belts, high plains, or maritime zones. Local knowledge is worth more than a coupon.
What changes for big pools and complex builds
Large freeforms with long plumbing runs need patience more than horsepower. Extending the blow time by a few minutes per line costs nothing and prevents spring repairs that cost plenty. Complex builds introduce branch points where air takes the path of least resistance. You can cheat that tendency with temporary caps or by feathering valves to steer flow. Remember that check valves can mask water trapped behind them. Crack unions to bleed that water out rather than cranking pressure.
Variable‑speed pumps, if used as an air mover, are a bad idea. I get the temptation, but the clearances and seals are designed for water, not air cavitation. Use a dedicated blower or compressor and leave the pump in hibernation.
When the cover finally goes on
A cover hides a thousand sins, so make sure there aren’t any. Vacuum leaves, brush the floor, and net the corners. Debris under a solid cover rots and feeds spring algae no matter how perfect your chemistry was at closing. For mesh safety covers, accept that some fine silt will find its way in. That’s a vacuum‑to‑waste date for April, not a reason to over‑chlorinate in October.
Check anchor threads, lube where needed, and replace any stretched springs. On irregular decks, lay out the cover, clip a few opposing corners, then walk around in a star pattern to even the tension. If a strap rubs a coping edge, add a wear pad. The small fixes you do now extend the cover’s life by seasons.
Spring starts in the fall
A careful inground pool closing feels like overkill until you open next year and the water is clear enough to see the main drain grate. Blowing out lines correctly is the heart of that outcome. Whether you hire an inground pool closing service or take pride in doing it yourself, the steps don’t change. Air before antifreeze, measured pressure, thoughtful sequencing, and a final pass over every fitting with your hand and your ear. The process is part science, part craft, and a small bit of superstition. I still give each Gizmo a friendly twist after the first cold night. It has never complained.
If you’re eyeing an above ground pool closing, give it the same respect with scaled‑down tools and a focus on cover security. If you need help and you’re in a climate that punishes delay, get on a schedule. A well‑timed, well‑executed closing buys you an easy spring, fewer repairs, and a pool that feels like an old friend when you pull the cover. That’s the quiet reward for an afternoon spent with a compressor, a bucket of plugs, and a healthy respect for expanding water.