Expert Tips by Pools Reno | Serving South Africa’s Pool Owners
Keeping your swimming pool free from algae is essential for both hygiene and aesthetics. In South Africa’s warmer climates—especially around Cape Town—algae growth can become a recurring issue. That’s where algaecide plays a vital role. This complete guide will help you understand how algaecide works, when to use it, and how to prevent common mistakes.
What Is Algaecide and What Does It Do?
Algaecide is a chemical treatment designed to kill and prevent algae in pool water. Available in both copper-based and non-metallic formulas, algaecide acts as a powerful supplement to your pool’s normal chlorine routine. While chlorine handles sanitisation, algaecide focuses specifically on algae control.
There are two main types of algaecide:
- Quaternary (Quat) algaecides: Foaming, but cost-effective and ideal for maintenance doses.
- Polyquats: Non-foaming, longer-lasting, and more suitable for treating visible algae outbreaks.
When Should You Use Algaecide?
Algaecide isn’t just a fix for green water. Instead, it works best when used preventatively. South African pool owners should consider adding algaecide:
- At the start of the swimming season (September–October)
- After heavy rainfall or storms
- After pool parties or heavy usage
- When closing your pool for winter
By staying ahead of algae growth, you’ll reduce the need for extreme chemical treatments later.
How to Apply Algaecide Correctly: Step-by-Step
- Balance Your Pool Water:
Ensure pH is between 7.2 and 7.6 for best results. Test and adjust before applying anything. - Brush the Pool Walls:
Remove any visible algae or dirt buildup. This improves chemical contact with problem areas. - Add Algaecide as Directed:
Read the instructions carefully and apply the correct dosage. For preventative use, lower doses are effective. For active algae, a stronger dose is needed. - Run the Pump and Filter:
Circulate the water for 6–8 hours to distribute the algaecide evenly across your pool. - Avoid Swimming Immediately After:
It’s recommended to wait 12–24 hours before swimming, depending on the product used.
Can You Use Too Much Algaecide?
Yes, and that’s a common mistake. Overusing algaecide can lead to:
- Foaming issues (especially with quats)
- Eye or skin irritation
- Metal staining in the case of copper-based algaecides
Tip: Always measure accurately and avoid doubling up on treatments “just in case.” Too much algaecide doesn’t improve performance—it can actually create new problems.
Algaecide vs Chlorine: What’s the Difference?
Many pool owners ask whether they need both chlorine and algaecide. The answer is yes—but for different reasons.
- Chlorine is your primary sanitiser. It kills bacteria, viruses, and algae.
- Algaecide specifically prevents algae from forming or reappearing.
When used together, they create a more robust sanitation strategy. Especially in coastal South African areas, where winds can introduce spores, a two-pronged approach is best.
Is Algaecide Safe for Fibreglass and Marbelite Pools?
Absolutely. Most modern algaecides are formulated to be safe for all pool surfaces—including fibreglass and marbelite. Still, always read the label to confirm compatibility and avoid products with harsh copper concentrations if you’re unsure.
Weekly Maintenance Tips for South African Pool Owners
To stay algae-free all year round:
- Keep your pool water balanced
- Shock your pool regularly
- Clean your filters
- Apply a maintenance dose of algaecide weekly
- Brush walls and vacuum often, especially in shaded or high-traffic areas
By sticking to this routine, your pool will remain clear and inviting even through peak summer in the Western Cape.
Frequently Asked Questions (FAQs)
Q1: Can I use algaecide and shock at the same time?
No. It’s better to shock your pool first, wait 24 hours, then apply algaecide. Doing both simultaneously can reduce their effectiveness.
Q2: How long should I wait before swimming after using algaecide?
Wait between 12 and 24 hours. Always follow the manufacturer’s instructions for safety.
Q3: Does algaecide replace chlorine?
Not at all. Algaecide supplements chlorine but doesn’t replace it. You still need regular chlorination for full sanitisation.
Q4: Will algaecide prevent algae from coming back?
Yes—if used consistently. Weekly maintenance doses, along with good cleaning and balanced water, keep algae at bay.
Q5: How much does algaecide cost in South Africa?
Prices range from R100 to R400 depending on the brand, size, and type. Non-foaming, long-lasting polyquat formulas tend to be on the higher end.
Q6: Can I use algaecide in a saltwater pool?
Yes, but ensure it’s labelled safe for saltwater systems. Most modern algaecides are compatible.
Q7: Why is my pool still green after using algaecide?
If the algae is severe, algaecide alone may not be enough. You may need to shock the pool and scrub all surfaces thoroughly. Consider calling a professional if the problem persists.
Pools Reno Can Help Keep Your Pool Algae-Free
At Pools Reno, we help Cape Town and Western Cape homeowners keep their pools pristine year-round. Whether you’re struggling with recurring algae or just need routine service, we offer:
- Deep chemical cleans
- Algae removal and prevention
- Water testing and rebalancing
- Chlorinator servicing and installations
- Regular pool cleaning plans
