Winterizing Your Pool in South Africa

If you've read American or European pool guides, you'll know they talk about draining pipes, blowing out lines, and adding antifreeze. Ignore all of that. South African winters are mild. In Gauteng, overnight lows rarely drop below 2-4 degrees Celsius. In the Lowveld (Nelspruit and surrounds), winter nights hover around 6-10 degrees. Neither region experiences freezing conditions that would damage plumbing or equipment. You do not need to drain your pool for winter.

What you do need to do is adjust your routine. Lower temperatures mean less evaporation, less algae growth, and less chemical demand. But "less" doesn't mean "none." A neglected pool in winter still goes green, especially during those warmer May and August days that catch people off guard. The goal is to reduce effort and cost while keeping the pool healthy enough that it takes one afternoon to bring it back to swimming condition in October.

Reduce Pump Run Time

In summer, you need 8-10 hours of filtration per day to maintain water quality. In winter, you can cut that to 4-6 hours. The water is cooler, bacteria and algae grow more slowly, and there are fewer swimmers adding contaminants. Less filtration means less electricity.

Set your timer to run during the warmest part of the day, typically 10:00-14:00 or 10:00-16:00. This is when any residual algae activity is highest and when the pump is most effective at circulating the treated water. Running the pump at night in winter achieves less because biological activity in cold water is minimal.

If you have a variable speed pump, drop it to a lower speed and run it for a longer period. A 6-8 hour low-speed run uses less electricity than a 4-hour full-speed run and gives better circulation.

Adjust Chemical Dosing

Cold water needs less chlorine. Algae growth slows dramatically below 15 degrees Celsius, and UV intensity is lower in winter, so chlorine lasts longer before breaking down. You can typically reduce your chlorine dosing to about half of what you use in summer.

Target levels remain the same:

• Free chlorine: 1-2 ppm (the lower end of the range is fine in winter).
• pH: 7.2-7.6. This doesn't change with the season.
• Total alkalinity: 80-120 ppm.
• Stabiliser (CYA): 30-50 ppm. Since UV is lower, 30 ppm is adequate in winter.

Test once a week. Even in winter, chemistry drifts. A quick test strip check takes 30 seconds and prevents the slow slide into green water that catches pool owners out in late winter.

One important note: if you use a salt chlorinator, it may have a "winter mode" that reduces output automatically based on water temperature. Check your unit's manual. If it doesn't, manually lower the chlorine output setting to about 50%. Running a salt chlorinator at full production in winter when demand is low leads to over-chlorination and high pH.

Cover the Pool

A pool cover is the single most impactful thing you can do for winter pool care. It reduces debris entry by 90% or more, cuts chemical loss, slows evaporation (which still happens, even in winter), and retains what little heat the water absorbs during the day.

For winter specifically, consider:

• A solid PVC safety cover. Keeps debris out, retains heat, and doubles as a child safety barrier. Best for pools that won't be used at all during winter. R15,000-R35,000 depending on pool size and material.
• A thermal/bubble cover (solar blanket). The affordable option. These translucent covers float on the surface, trap heat, and reduce evaporation. They don't offer safety compliance and they're not designed to bear weight, but they're effective at keeping the pool warmer and cleaner. R2,000-R6,000 depending on pool size.
• A debris cover (leaf net). A lightweight mesh that sits over the pool and catches leaves. It doesn't retain heat or reduce evaporation, but if your pool is near trees and leaves are the main winter problem, it's a practical solution. R1,500-R4,000.

If budget allows, a solid safety cover is the best winter investment. It solves safety, debris, heat loss, and evaporation in one product.

Clean Before You Cover

Don't just throw a cover on a dirty pool. Before covering for winter, do a thorough clean:

• Brush the walls and floor to dislodge any algae starting to form.
• Vacuum the pool thoroughly.
• Clean the skimmer basket, pump basket, and filter.
• Backwash the sand filter or clean the cartridge.
• Test and balance all chemicals.
• Add a dose of algaecide as a preventative measure.

Starting winter with a clean, balanced pool means less work to maintain it through the cold months.

Equipment Maintenance

Winter is the ideal time to inspect and service equipment while you're not relying on it daily.

• Pump and motor. Listen for unusual noise. A grinding or screeching sound means the bearings are wearing. Better to address it now during the quiet season than have the pump fail on the first hot weekend in September.
• Filter. If you have a sand filter, check when you last changed the sand. Filter sand should be replaced every 3-5 years. If it's overdue, winter is the time. For cartridge filters, inspect the cartridge for tears, collapse, or discolouration and replace if needed.
• Kreepy Krauly or automatic cleaner. Remove it from the pool if you're covering. Leaving it in under a cover causes unnecessary wear on the diaphragm and hoses. Store it in a shaded area. Check the diaphragm, foot, and hoses for cracks or wear. Replacement parts are inexpensive and available at both our branches.
• Salt chlorinator cell. Inspect the cell for calcium buildup. If the plates are coated, soak the cell in a mild acid solution (1 part hydrochloric acid to 10 parts water) for 5-10 minutes, then rinse. A clean cell works efficiently when you need it in spring.
• O-rings and seals. Check the pump lid O-ring, multiport valve O-ring, and any other seals. Apply a thin layer of silicone lubricant to keep them supple. Dried-out O-rings crack and cause air leaks that reduce pump performance.

Gauteng vs Lowveld: Regional Differences

Our two branches serve different climates, and pool care differs slightly between them.

Gauteng (Roodepoort)

• Dry, cold winters with occasional frost on the Highveld.
• Water temperatures drop to 10-14 degrees Celsius by July.
• Minimal algae risk in the coldest months (June-July), but watch May and August when afternoon temps can still reach 22-25 degrees.
• Evaporation continues due to low humidity. A cover is especially valuable here.
• Run the pump 4-5 hours per day in midwinter. Increase to 6 hours in late August as temperatures rise.

Lowveld (Nelspruit)

• Milder winters. Daytime temperatures often reach 25-28 degrees even in June and July.
• Water temperatures rarely drop below 16-18 degrees.
• Higher algae risk than Gauteng. The warmer water means you can't reduce chemicals as aggressively.
• Run the pump 5-6 hours per day minimum, even in midwinter.
• Keep chlorine closer to 2 ppm rather than dropping to 1 ppm.
• Some Lowveld pool owners swim year-round. If that's you, maintain near-summer chemical levels and pump times.

Monthly Winter Checklist

Here's a simple routine to keep your pool healthy through winter with minimal effort:

• Test water once per week (pH and chlorine). Adjust as needed.
• Add chlorine as required. Typically half your summer dose.
• Remove the cover once a week to check the water and let sunlight in for a few hours.
• Skim any debris that's accumulated.
• Check the pump and filter are running correctly.
• Backwash the filter once a month (or when pressure rises 8-10 psi above clean).
• Empty skimmer and pump baskets.
• Bring a water sample to Ridd's once a month for a comprehensive check.

Total time: about 20-30 minutes per week. That's all it takes to keep the pool ticking over through winter and avoid a costly green pool recovery in spring.

What Not to Do

• Don't drain the pool. There's no reason to in South Africa. An empty pool is at risk of lifting out of the ground due to hydrostatic pressure from groundwater, and the exposed surfaces can crack and deteriorate.
• Don't turn the pump off completely. Stagnant water breeds algae and bacteria even in winter. The pump must run daily.
• Don't stop testing. "It's winter, the pool is fine" is how people end up with a swamp by August. Test weekly.
• Don't ignore the filter. A dirty filter in winter means poor circulation and cloudy water by spring. Keep it maintained.

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