How To Winterise Your Fibreglass Pool Properly

As the temperatures start to drop and the swimming season comes to an end, many Australian pool owners may wonder how best to prepare their fibreglass pool for winter. Proper winterisation helps, protects pool equipment, and ensures an easier opening when summer returns. Unlike concrete or vinyl pools, fibreglass pools require specific care to prevent algae growth, surface damage, and equipment issues.

Without proper winter maintenance, your pool water can become cloudy, algae-ridden, and difficult to restore when the warm weather returns. Additionally, neglecting your pool during winter can lead to costly repairs due to damage caused by freezing conditions or chemical imbalances. By taking a few proactive steps now, you can ensure your maintenance for your pool remains in top condition year-round, making it easier to dive back in when summer arrives.

In this guide, we will take you through the essential steps to winterise your fibreglass pool properly, ensuring it stays in great condition during the colder months.

1. Balance Your Pool Water

Before closing your pool for the season, it’s crucial to test and balance the water chemistry. Properly balanced water prevents algae growth, staining, and scaling, which can be difficult to clean when reopening the pool.

Key Levels to Check:

• pH: Aim for a pH level between 7.2 and 7.6.
• Alkalinity: Maintain a total alkalinity level between 80-120 ppm.
• Calcium Hardness: Keep calcium hardness within 200-400 ppm to prevent scaling on the fibreglass surface.
• Chlorine: Ensure free chlorine levels are between 1-3 ppm.
• Cyanuric Acid: Maintain between 30-50 ppm to stabilise chlorine levels.

Use a reliable test kit or take a water sample to your local pool shop for professional testing.

2. Thoroughly Clean the Pool

A clean pool is easier to maintain throughout winter. Debris and organic matter left in the water can cause algae growth, stains, and bacteria build-up.

Cleaning Steps:

• Use a pool vacuum to remove dirt and debris from the floor and walls.
• Brush the walls and steps to prevent algae from clinging to surfaces.
• Skim the water surface to remove leaves, bugs, and other floating debris.
• Empty and clean out the skimmer and pump baskets.

If you have a pool cover, make sure it is clean and free from debris before placing it over the pool.

3. Shock the Pool Water

Shocking your pool helps to kill any lingering bacteria or algae spores. Use a high-quality chlorine shock treatment and follow the recommended dosage on the packaging. Allow the pool pump to run for at least 24 hours to distribute the shock treatment evenly.

If you are using a non-chlorine shock, ensure that it is compatible with your pool system. After shocking, re-test the water chemistry and adjust if necessary.

4. Lower the Water Level (If Necessary)

Unlike vinyl or concrete pools, most fibreglass pools do not require a drastic drop in water levels. However, if you live in an area prone to heavy rain or storms, lowering the water level slightly below the skimmer can prevent overflow.

Be careful not to drain too much water, as fibreglass pools rely on the surrounding water pressure to prevent structural damage.

5. Protect the Pool Equipment

Your pool’s filtration system, pump, and heater need proper care to ensure they remain in good condition over the winter months.

Steps to Protect Your Equipment:

• Backwash and clean the filter to remove built-up debris.
• Turn off and drain the pump, filter, heater, and chlorinator to prevent water from freezing inside the equipment (if applicable to your region).
• Remove and store pool accessories, including ladders, pool toys, and automatic cleaners.
• Lubricate O-rings and seals to prevent cracking and damage.

If you live in a region where temperatures drop significantly, consider using pool antifreeze in plumbing lines to prevent freezing damage.

6. Add a Long-Lasting Algaecide

To keep your fibreglass pool clear and free of algae during winter, add a long-lasting algaecide. This prevents algae from forming even when chlorine levels drop over time. Choose a product specifically designed for fibreglass pools and follow the manufacturer’s instructions.

7. Cover Your Pool

Using a high-quality pool cover is one of the best ways to protect your pool during winter. A good cover prevents debris, leaves, and rainwater from contaminating the pool, reducing maintenance.

Choosing the Right Pool Cover:

• Winter Pool Covers: Heavy-duty covers designed to keep out debris and sunlight, reducing the chance of algae growth.
• Safety Covers: A strong, mesh-style cover that prevents accidents and keeps the pool secure.
• Automatic Covers: A convenient option that can be opened and closed with the push of a button.

Ensure the cover is properly secured and free of tears or damage.

8. Monitor Your Pool During Winter

Even though your pool is not in use, occasional maintenance is necessary to keep it in good condition.

Ongoing Winter Maintenance:

• Check the water chemistry once a month and adjust as needed.
• Remove debris that accumulates on the pool cover.
• Inspect the pool equipment to ensure everything remains in working order.
• Run the pump occasionally to prevent stagnation and water quality issues.

9. Prepare for Reopening in Summer

As the weather starts to warm up, begin preparing your pool for the swimming season. Remove the cover, check the water levels, and test the chemical balance. If needed, shock the pool again and run the filtration system for 24-48 hours to circulate fresh chemicals.

Give the pool a deep clean and inspect all equipment for any signs of wear or damage before reopening.

Final Thoughts

Winterising your fibreglass pool properly ensures that it remains in top condition throughout the colder months, reducing maintenance and making summer reopening a breeze. By balancing your pool water, cleaning thoroughly, protecting equipment, and using a quality pool cover, you can prevent common issues such as algae growth, stains, and equipment damage.

Taking the time to winterise your pool correctly will save you both time and money in the long run, ensuring your fibreglass pool remains an enjoyable and stress-free feature of your home. If you’re unsure about any step, consult a pool professional for guidance tailored to your specific pool and climate conditions.

With these steps in place, you can enjoy peace of mind knowing your pool is well-maintained and ready for the next swimming season!