How to Prepare Your Pool for Winter in Gauteng
Gauteng winters are dry and sunny by day, with cold, clear nights and frost in low-lying areas. It does not get cold enough here to freeze a pool the way it does in the northern hemisphere, so there is no reason to "close" a pool for the season. But a pool that is simply ignored from May to August is the most common reason for a green pool, a stained surface or a seized pump in September. This guide explains how to run a pool through a Highveld winter with less effort, and why winter is the best time of year for the bigger jobs.
Should I drain my pool for winter?
No. Draining a pool in Gauteng for winter brings risk and no benefit. An empty shell can be damaged by groundwater pressure or by the sun, a fibreglass pool can lift or distort, and refilling uses a great deal of municipal water. Keep the pool full, the pump running and the water balanced. The only reason to drain in winter is a specific job such as an acid wash or a repair, and then only for as long as the job takes.
How many hours should the pump run in winter?
Fewer than in summer, but never none. With colder water, fewer swimmers and weaker sun, algae grows more slowly and chlorine lasts longer, so four to six hours a day is usually enough for a family pool, against six to eight in summer. Run it in the warmest part of the day if you can, and check the timer after any power cut, because an outage can knock it out of sync without anyone noticing. Add hours after a windy spell or a rare winter shower.
How should I adjust the chemistry for winter?
- Keep chlorine present, at the lower end of the range — around 1–2 ppm free chlorine. Turn a salt chlorinator's output down rather than off.
- Keep pH at 7.2–7.6 and total alkalinity at 80–120 ppm. Cold water does not stop scale forming if the pH is left high, and Gauteng's hard water will show it along the tile line.
- Test at least every two weeks, and weekly if the pool collects leaves or dust.
- Consider a phosphate remover or an algaecide at the start of winter as an extra margin, especially if the pool sits under trees.
- Shock the pool before you start the lighter routine, so it goes into winter clean.
What winter maintenance should I still do?
Every week or two:
- Skim leaves and empty the weir and pump baskets. Autumn leaves that sink and lie on the floor for weeks leave tannin stains.
- Brush the walls and steps.
- Check that the pump runs when the timer says it should.
- Backwash when the pressure gauge says so — usually less often than in summer.
Once a month, look over the equipment: listen to the pump, check under it for drips, look at the salt cell for white scale, and check the chlorinator's readings. A heater that is not in use should be switched off at its controller, with the area around it kept clear of leaves.
How do frost, wind and dust affect a winter pool?
Frost on a clear Highveld morning does not harm a pool that is full and circulating, but exposed pipes and a pump box in a hollow where cold air settles are worth a look: a cracked fitting or a perished O-ring often shows itself on the first cold mornings. August and September bring the wind. It blows dust, dry grass and the last of the autumn leaves into the pool, and it pulls water out through evaporation faster than you might expect in cold weather. Empty the baskets after windy days, brush the dust off the steps before it settles into a film, and keep the level up so the weir does not start sucking air. If the pool sits under deciduous trees, a cover through autumn saves weeks of skimming.
Is a pool cover worth it in winter?
For many pools, yes. A cover keeps out leaves and the dust that blows in August and September, cuts evaporation (Highveld winter air is very dry), reduces chemical use and holds some heat. It will not stop a pool turning green if the pump does not run and nobody checks the water, but it makes the routine much lighter. A floating solar blanket is not a safety device, so it does not replace a fence. Fitting a cover is R500 in labour, with the cover measured and quoted separately; see pool covers.
Why is winter the best time for an acid wash or a sand change?
The pool is out of use, there is no rush, and the ground is dry.
- Acid wash. An acid wash needs an empty pool, and an empty pool is safest in the dry months, when the groundwater pressure under the shell is low and the sun is gentler on a freshly washed surface. If your surface is scaled or stained, an acid wash at R3,500 in June or July means the pool is refilled and balanced before September.
- Sand change. If the water was hard to keep clear last summer, or the pressure climbs straight back after a backwash, change the sand in winter so the filter starts spring fresh. A sand change is priced by the number of bags your filter takes, from R1,450 for a 3-bag filter.
- Repairs. Leaks, weir cracks, lights and valves are all easier to fix when nobody needs the pool.
- Chlorinator service. Clean a scaled salt cell before summer's chlorine demand arrives. A chlorinator service is R1,299 and covers cleaning the cell and inspecting the unit.
Should I keep my pool service going over winter?
We recommend it. A pool with nobody checking it through winter is the pool most likely to need a green pool recovery in September. If you are on a weekly pool maintenance plan, talk to us before winter about what your pool needs: the water still has to be balanced and the pump still has to run, even when nobody swims.
How do I get the pool ready for spring?
From late August:
- Take off and clean the cover.
- Clear the leaves and empty the baskets.
- Brush the whole pool.
- Backwash and rinse the filter, or change the sand if it is due.
- Test and balance: alkalinity first, then pH, then chlorine.
- Shock the pool.
- Increase the pump hours gradually as the days warm up.
- Check the pump, filter, chlorinator and timer before the first hot weekend.
Frequently asked questions
Can I switch the pool pump off for winter?
No. Still water grows algae even in winter, and restarting a pump that has stood for months can reveal a seized motor or a perished seal.
Why does my pool lose so much water in winter?
Highveld winter air is very dry and often windy, so evaporation continues even when it is cold. If the loss seems too high, do a bucket test before assuming a leak — see pool leak detection.
Why is my pool green in September?
Usually because the pump ran too few hours and nobody tested the water through winter. Shock, brush, filter and vacuum to waste — or have it recovered.
Should I heat the pool in winter?
Only if you will use it, and only with a cover on it every night. Read pool heating options in South Africa before you decide.
Talk to us
We work across Pretoria, Centurion and Midrand. WhatsApp or call Crystal Reef on 081 577 5051, or email sales@crystalreef.co.za. For the details of the biggest winter job, read acid washing your pool.