Cape Town ponds face hot, windy, dry summers and cool, rainy winters. In summer, watch for evaporation, algae and low oxygen. In autumn, keep leaves out and service the pump. In winter, watch for overflow and garden run-off and feed fish very little. In spring, restart feeding slowly and get the filter and UV ready for the algae season.
Summer (December to February)
- Evaporation. Hot days and the south-easter can drop the level fast. Top up with tap water treated with a pond water conditioner, a little at a time.
- Algae. Long, sunny days plus warm water are perfect for green water and string algae. Shade about a third to half of the surface with water lilies or other floating plants.
- Oxygen. Warm water holds less oxygen, and it's lowest just before dawn. Keep the pump and any fountain or air pump running 24 hours a day.
- Feeding. Fish are most active now and can be fed more, but still only what they finish in a few minutes.
Autumn (March to May)
- Leaves. Fallen leaves sink, rot and foul the water. A pond net over the surface, or regular skimming, saves a lot of trouble.
- Feeding. Cut back as the water cools.
- Service before winter. Clean the pump intake and filter, and check for wear before the wet months.
Winter (June to August)
Winter is Cape Town's rainy season, and that's where most winter pond problems come from.
- Overflow. Heavy rain can flood a pond and wash fish out. Make sure there's an overflow point and it isn't blocked.
- Run-off. Rain washes fertiliser, compost and garden sprays from flower beds and lawns into the pond. Build up the edges so garden water runs away from it.
- Feeding. Fish slow right down in cold water. When the water is around 10 °C or colder, koi and goldfish need little or no food. Uneaten food just rots.
- Keep the filter running. Switching it off for winter kills the good bacteria, and spring starts badly.
Spring (September to November)
- Restart feeding gradually as the water warms and fish become active.
- Clean the filter (in pond water, not tap water) and check the pump flow.
- UV clarifier. Replace the UV bulb if it's been running about a year. Bulbs still glow long after they stop working on algae.
- Check fish health. Fish come out of winter with weaker immune systems. Watch for sores, fin damage or fish sitting on the bottom.
Through the year
| Job | How often |
|---|---|
| Check the pump and skimmer are clear | Weekly |
| Partial water change (10 to 20%) with conditioned water | Monthly |
| Rinse filter media in pond water | Monthly, or when flow drops |
| Test water (ammonia, nitrite, pH, KH) | Monthly |
| Trim plants, remove dead leaves and debris | Monthly |
| Replace UV bulb | About once a year |
Our pond maintenance
We maintain garden and koi ponds across Cape Town on a regular schedule: pumps and filters checked and cleaned, water tested and treated, debris removed, and fish checked. Ponds are priced per pond, based on size and setup. For the bigger picture on keeping pond water clear, read green water and other pond problems and koi pond filters, pumps and UV.
Keep your pond clear all year
Send us a photo and the size of your pond and we'll quote a regular maintenance plan.