Why does my pool keep turning green ?
If your pool keeps turning green, it is usually a sign that something is allowing algae to grow faster than your pool can control it. There are several possible causes, from water chemistry issues to problems with your pool equipment.
1. Your chlorine level is too low
Chlorine is what keeps algae under control. During periods of hot weather, heavy rain, or increased pool usage, your pool may use chlorine faster than usual. If the sanitiser level drops too low, algae can quickly begin to multiply and turn your pool green.
2. Your filtration system is not running long enough
Your pool pump and filter play an important role in keeping your water clean. Good circulation helps distribute chlorine throughout the pool and allows the filter to capture fine particles, debris, and dead algae.
If your pump is not running for enough hours each day, areas of the pool may have poor circulation, creating conditions where algae can grow.
3. Your filter needs cleaning
Your pool water constantly passes through your filter, which traps dirt, debris and other contaminants. However, when a filter becomes dirty or clogged, its ability to remove impurities is reduced.
A blocked filter can lead to poor water circulation and allow algae to grow more easily. Regular filter cleaning is essential to keep your filtration system working efficiently.
4. Your chlorinator is not producing enough chlorine
If you have a saltwater pool, your chlorinator may not be producing enough chlorine to meet your pool’s needs. This can happen for several reasons, such as a low salt level, an output setting that is too low, or an ageing or damaged chlorinator cell.
When chlorine production cannot keep up with chlorine demand, algae can quickly take advantage of the imbalance.
Alex’s Advice💡
The best way to prevent your pool from turning green is through regular maintenance and early detection of small problems. I always recommend working with a local pool professional who can keep your water chemistry balanced, inspect your equipment, and identify potential issues before they become costly repairs.
If regular professional servicing isn't within your budget, you can still keep your pool in great condition by following these simple tips:
Test your water regularly. Take a water sample to your local pool shop or Bunnings for a free water analysis.
Clean your filter every 2–3 months, or more frequently if the pressure gauge indicates it needs cleaning.
Run your filtration system for long enough each day. As a general guide, your pump should circulate the entire volume of your pool 1 to 1.5 times per day in winter and 2 to 2.5 times per day in summer. The required running time depends on your pump's flow rate and your pool's size.
Inspect your salt chlorinator cell regularly for calcium build-up, as this can reduce chlorine production.
Adjust your chlorinator output during summer and periods of heavy pool use to meet the increased chlorine demand.
Keep your pump and skimmer baskets clean to maintain good water circulation and reduce strain on your equipment.
If you'd like to have your pool casually checked, I also offer one-off pool services. During the visit, I'll thoroughly clean your pool, test and balance the water, and inspect your equipment to ensure everything is operating correctly.
If you have any concerns about your pool or simply want a professional health check, feel free to get in touch or book a service. Catching small issues early is almost always easier than recovering a green pool.
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