Fibreglass swimming pools Perth are a fantastic addition to any Australian backyard, offering
durability, smooth finishes, and low maintenance compared to concrete pools. However,
proper water chemistry is essential to keeping your pool clean, safe, and long-lasting. Using
the right pool chemicals not only ensures clear water but also prevents damage to your
fibreglass shell.
In this guide, we’ll explore the best pool chemicals for fibreglass pools, how they work, and
how to use them effectively.
Why Choosing the Right Chemicals Matters
Maintaining a fibreglass pool isn’t just about keeping the water looking pristine—it’s about
protecting the pool structure, the filtration system, and the health of swimmers. Using the
wrong chemicals or incorrect dosages can lead to problems like:
● Staining or discolouration of the pool surface
● Cloudy or murky water
● Algae growth
● Damage to the gel coat
● Skin and eye irritation for swimmers
By using the correct pool chemicals, you can avoid these issues and extend the lifespan of
your fibreglass pool.
The Essential Pool Chemicals for Fibreglass Pools
● Liquid Chlorine – Ideal for regular pool maintenance, liquid chlorine disperses
quickly and leaves no residue.
● Saltwater Chlorinators – A great alternative for those who prefer a gentler
approach, as they generate chlorine from salt and maintain stable levels.
● Stabilised Chlorine (Trichlor or Dichlor) – Helps maintain chlorine levels in
outdoor pools by preventing rapid breakdown from UV rays.
� Tip: Avoid calcium-based chlorine (like calcium hypochlorite), as it can cause scaling on
fibreglass surfaces.
2. pH Balancers – Maintaining Water Balance
The ideal pH level for fibreglass pools is between 7.2 and 7.6. If the pH is too high, the water
becomes cloudy, and chlorine loses effectiveness. If too low, the water becomes corrosive
and can damage the pool surface.
● pH Increaser (Sodium Carbonate / Soda Ash) – Used when pH is too low.
● pH Decreaser (Muriatic Acid or Dry Acid) – Used when pH is too high.
Regular testing with a pool water test kit is essential to ensure the pH stays within the
recommended range.
3. Algaecides – Preventing Algae Growth
Algae can quickly take over a pool if chlorine levels drop or water circulation is poor. Using
an algaecide can help prevent and eliminate algae before it becomes a bigger problem.
● Copper-Based Algaecides – Effective against green, black, and mustard algae.
However, overuse can lead to metal stains.
● Non-Copper Algaecides (Quaternary Ammonium Compounds) – A safer option
for fibreglass pools as they don’t cause staining.
� Tip: Use algaecide as a preventative measure, especially during warmer months when
algae growth is more common.
4. Calcium Hardness Control – Protecting Your Pool Surface
Although fibreglass pools don’t require as much calcium as concrete pools, water that’s too
soft (low calcium levels) can become corrosive and damage equipment. The ideal calcium
hardness level is 150–250 ppm.
● Calcium Hardness Increaser (Calcium Chloride) – Raises calcium levels if they
are too low.
Avoid excessive calcium levels, as they can cause scale buildup on pool walls and
equipment.
5. Cyanuric Acid – Protecting Chlorine from UV Rays
Cyanuric acid (CYA) is a chlorine stabiliser that protects chlorine from breaking down
under the sun’s UV rays. Without stabiliser, chlorine levels can deplete rapidly, requiring
more frequent dosing.
● Ideal CYA Level: 30–50 ppm
● How to Add It: Cyanuric acid is available in liquid or granular form and should be
added gradually to avoid overdosing.
� Tip: If you use stabilised chlorine (Trichlor or Dichlor), be cautious, as it already
contains cyanuric acid. Too much can reduce chlorine effectiveness.
6. Shock Treatments – Deep Cleaning Your Pool
Even with regular chlorine use, contaminants like sunscreen, body oils, and organic matter
can build up, making the water dull and reducing chlorine efficiency. That’s where pool
shock comes in.
● Calcium Hypochlorite Shock – Strong but can leave residue, making it less ideal
for fibreglass pools.
● Non-Chlorine Shock (Potassium Monopersulfate) – A great option for fibreglass
pools, as it oxidises contaminants without adding extra chlorine.
� Tip: Shock your pool every 1–2 weeks, especially after heavy rainfall or pool parties.
7. Total Alkalinity Increaser – Keeping pH Stable
Total alkalinity (TA) acts as a buffer for pH levels, preventing rapid fluctuations that can lead
to water imbalance. The ideal total alkalinity level for fibreglass pools is 80–120 ppm.
● Total Alkalinity Increaser (Sodium Bicarbonate / Baking Soda) – Raises alkalinity
while having a minor effect on pH.
● Muriatic Acid or Dry Acid – Used to lower alkalinity if it becomes too high.
� Tip: If pH is fluctuating frequently, check your total alkalinity levels, as imbalances often
cause instability.
Best Practices for Using Pool Chemicals
Test Your Water Regularly
Regular water testing is the key to balanced pool chemistry. Use a liquid test kit or test
strips at least twice a week to monitor:
● pH
● Chlorine levels
● Alkalinity
● Calcium hardness
● Cyanuric acid
Always Add Chemicals Gradually
Dumping chemicals in all at once can cause imbalances or damage the pool surface.
Instead:
● Pre-dissolve granular chemicals in a bucket of water before adding.
● Pour liquids slowly around the pool while the pump is running.
Avoid Mixing Chemicals Directly
Some chemicals react dangerously when mixed, releasing harmful fumes or causing pool
staining. Always add them separately and allow time for circulation.
Avoid Mixing Chemicals Directly
Some chemicals react dangerously when mixed, releasing harmful fumes or causing pool
staining. Always add them separately and allow time for circulation.
Run Your Pool Pump After Adding Chemicals
After adding chemicals, run your pool pump for at least 4–6 hours to ensure even
distribution.
Store Pool Chemicals Properly
Keep chemicals in a cool, dry place away from direct sunlight and moisture. Ensure lids are
tightly sealed to prevent contamination.
Final Thoughts
Maintaining a fibreglass pool is easier than many other pool types, but the right chemicals
are essential for keeping the water clear and the pool surface in top condition. By using the
proper sanitiser, balancing pH, preventing algae, and shocking the pool when needed, you
can enjoy a pristine swimming environment all year round.
Regular testing and proactive care will help extend the life of your fibreglass pool, prevent
costly repairs, and ensure safe swimming conditions for you and your family.
Need Expert Advice?
If you’re unsure about which chemicals to use or need help balancing your pool water,
consider reaching out to your local pool professional for guidance. With the right
approach, your fibreglass pool will stay sparkling clean for years to come!
