Algaecide: The Effective Way to Prevent Algae
As the weather starts to cool down, many pool owners are asking what they should be doing to “winterise” their pool. While every pool and setup is slightly different, one important step often included in winter maintenance is adding a maintenance dose of algaecide.
Algae can develop if pool water becomes unbalanced or circulation and sanitising levels drop, and winter can sometimes allow algae problems to go unnoticed for longer because pools are generally used less frequently and checked less often.
Algaecides can help reduce the likelihood of algae developing during these lower-maintenance periods, but there is often confusion around what they do, when they should be used and which type is best.
The good news is that algaecides are fairly straightforward once you understand the basics. Different products are designed for different purposes, and choosing the right one usually depends on your current setup and whether you are trying to prevent algae or actively treat it.
How Algaecides Work
Algaecides are designed to interfere with algae growth and reproduction in pool water. Different products work in different ways, which is why some are better suited to prevention while others are more effective during active algae treatment.
Copper-based algaecides release copper ions into the water which enter algae cells and disrupt important cellular processes. This damages the algae and interferes with its ability to produce energy through photosynthesis which eventually causes it to die.
Copper-free algaecides primarily work by targeting the cellular structures of algae, suffocating them or breaking down the bonds that allow them to multiply.
Maintenance Dosing
A common misconception is that algaecide is only necessary once a pool has already turned green. In reality, we suggest a quarterly dose as part of preventative maintenance, particularly during periods where algae is more likely to develop.
This can include:
- Winter maintenance
- Hot weather
- Increased pool usage
- Storm activity
- Water balance fluctuations
- Reduced filtration time
- Pools surrounded by trees or organic debris
Used preventatively, algaecide can help reduce the likelihood of algae establishing itself in the first place. Once algae becomes visible, particularly if the water has turned green or surfaces are becoming slippery, treatment generally becomes more aggressive and may involve brushing, vacuuming, regular filter cleaning and water balancing alongside higher-cost chemical treatment.
Copper Algaecides
Copper-based algaecides are generally stronger treatment products and are often used during green pool recoveries or where algae keeps returning despite regular maintenance. It is also a popular maintenance product as the copper remains latent in the water and can provide long-lasting prevention.
Because of this, it is important that dosing instructions are followed carefully and copper levels have been tested prior to application. Over time, excessive copper levels may contribute to staining or discolouration under certain water conditions. This is why accurate water testing and balanced chemistry are still important when using copper-based products.
When To Avoid Copper Algaecides
- Your pool has a gas heating system
- Your pool uses an ioniser sanitation system
- Your pool water’s copper levels are already above the recommended range
Copper-Free Algaecides (Benzalkonium Algaecide)
Copper-free algaecides such as Benzalkonium algaecides are commonly used as preventative maintenance products. Unlike copper-based products, they don’t remain active in the water for extended periods so they generally require more regular maintenance dosing to remain effective.
One thing to be aware of is that Benzalkonium can sometimes create foaming, particularly if overdosed, though following dosage instructions carefully will usually help minimise this. In most cases the foam is harmless and typically dissipates on its own within a few days as the chemical circulates and filters.
When to Consider a Copper-Free Algaecide
- Your pool already has elevated copper levels
- Your pool has a gas heater installed
- Your pool uses an ioniser sanitation system
- You want an algae prevention option without introducing metals to the water
Other Ways to Help Prevent Algae
While algaecide can play an important role in algae prevention, it generally works best as part of a consistent overall maintenance routine. In many cases, recurring algae problems are linked to underlying water balance or filtration issues.
These practical habits can make a significant difference to long-term algae prevention:
- Test your pool water regularly: ensure chlorine and water balance levels remain within range
- Remove leaves and debris from the pool before they break down
- Treat phosphates where necessary: phosphates act as a food source for algae
- Run your filtration system long enough each day: you should never cease filtration completely, generally filter for 4 hours in winter depending on pool size
- Clean your filter regularly: this ensures circulation and filtration remain effective
- Brush pool walls and steps: prevents algae building up in low-circulation areas
- Check baskets, pumps and returns are flowing properly: avoids dead spots in the pool
Generally speaking, pools that maintain good circulation, balanced water and regular maintenance tend to experience far fewer algae issues.
Final Thoughts
Algaecides can become a complimentary part of pool care when used correctly. Understanding the difference between copper-based and copper-free algaecides helps make it easier to choose the right product for your pool.
If you’re unsure which algaecide is best suited for your pool, bring a water sample into the store and we can help guide you through the most practical option for your water condition and maintenance routine, “because everybody deserves a safe and healthy pool”.
