Remove Stubborn Pool Stains — Organic & Mineral Treatment

Understanding Pool Stains in Perth

Pool stains are one of the most common cosmetic issues for Perth pool owners. Even well-maintained pools can develop stains over time due to factors specific to Western Australia’s water supply, climate, and vegetation. What starts as a small mark on the pool floor or wall can gradually spread and deepen, making your pool look dirty even when the water itself is perfectly clean and safe.

The good news is that most pool stains can be treated effectively with the right approach. The key is correctly identifying the type of stain, because different stain types require completely different chemical treatments. Applying the wrong treatment wastes money and can sometimes make the stain worse.

Types of Pool Stains

Organic Stains

Organic stains are caused by plant matter that sits on the pool surface and releases tannins into the material. In Perth, the most common sources are eucalyptus leaves, jacaranda flowers, and fallen fruit from fig and mulberry trees — all common in suburbs like Nedlands, Dalkeith, Mount Claremont, and Claremont where mature gardens are prevalent.

Organic stains typically appear as brown, green, or reddish-brown marks, often in the shape of the leaf or debris that caused them. They are most common on the pool floor and steps where debris settles. These stains are generally the easiest type to treat and respond well to chlorine-based oxidation or ascorbic acid treatments.

Mineral Stains

Mineral stains are a particular problem in Perth due to the widespread use of bore water to fill and top up pools. Perth’s groundwater is naturally high in calcium, iron, and manganese. When these minerals precipitate out of solution — often triggered by a sudden change in pH or alkalinity — they deposit on pool surfaces as stains.

Calcium staining appears as white or grey scale deposits, often along the waterline or on areas where water frequently splashes and evaporates. Calcium buildup is not just cosmetic — it can roughen pool surfaces and clog equipment.

Iron staining produces rusty brown or orange marks. Iron can enter the pool through bore water, corroding metal fittings, or cheap imported pool equipment with exposed ferrous components.

Manganese staining creates dark brown, purple, or black marks. Like iron, manganese is present in Perth’s bore water and stains surfaces when it oxidises.

Metal Stains

Metal stains differ from mineral stains in that they typically originate from pool equipment or chemicals rather than the water source. Copper stains — which appear blue-green or turquoise — are often caused by corroding copper heat exchangers in pool heaters, or by the overuse of copper-based algaecides. Metal objects accidentally left in the pool, such as hair clips, coins, or screws, can also leave localised rust stains.

Our Stain Removal Process

Accurate Identification

Before any treatment begins, we need to know exactly what type of stain we are dealing with. We use spot testing methods to identify the stain type:

• Ascorbic acid (vitamin C) test: A crushed vitamin C tablet is held against the stain. If the stain lightens or disappears, it indicates a metal or mineral stain.
• Trichlor tablet test: A chlorine tablet is held against the stain. If the stain lightens, it is organic in nature.

This simple but effective diagnostic step ensures we select the right treatment the first time.

Surface-Safe Treatment

Different pool surfaces require different treatment approaches. We adjust our methods based on whether your pool is fibreglass, pebblecrete, rendered concrete, tiled, or vinyl-lined.

For organic stains, we typically use a combination of elevated chlorine levels and direct application of oxidising agents. Stubborn organic stains may require an ascorbic acid treatment to lift the tannin discolouration from the surface.

For mineral and metal stains, we use sequestrant-based treatments that chelate the metal ions and lift them from the surface back into solution, where the filtration system can remove them. In severe cases, a full ascorbic acid treatment of the entire pool may be required, followed by a sequestrant course to prevent re-staining.

Prevention Strategy

Removing stains is only half the solution. Without addressing the underlying cause, stains will return. We provide practical, specific advice based on your situation:

• If bore water is the issue, we recommend a sequestrant maintenance programme to keep dissolved metals in solution
• If organic debris is the cause, we advise on pool cover use, skimmer upgrades, or increased service frequency during autumn
• If equipment corrosion is contributing, we identify the source and recommend repair or replacement

Pricing for Pool Stain Removal

Our stain removal service is priced from $200 to $500 depending on the type of stain, the area affected, and the pool surface material. Simple organic stain treatments on fibreglass pools are at the lower end, while full-pool metal stain treatments on pebblecrete surfaces are at the upper end.

We provide an accurate quote after assessing your pool. For pools with severe or widespread staining, a drain-and-acid-wash may be more effective and cost-efficient than surface stain treatment — we will advise you honestly on the best approach.

Get Your Pool Looking Its Best

Whether your pool has leaf stains on the floor, iron marks from bore water, or a mysterious discolouration you cannot identify, we can help. We service pools across Perth including Mount Claremont, Nedlands, Subiaco, Cottesloe, Scarborough, and all surrounding suburbs. Contact us today for a stain assessment and quote.