How to Remove Pool Stains: Expert Tips for Sparkling Clean Surfaces

One of the most common challenges pool owners face is dealing with stains that form on the pool’s surfaces. These stains, which can appear on the walls, floors, or waterline, are not only unsightly but can also detract from your pool’s overall appearance and enjoyment. Whether it’s mineral buildup, algae, or dirt, the key to maintaining a sparkling clean pool is knowing how to remove these stains effectively.

Understanding the causes of pool stains and the best methods to remove them is essential to preserving the beauty of your pool. In this guide, we will walk you through expert tips on how to tackle different types of stains, restore your pool surfaces, and prevent future stains from forming.

Common Types of Pool Stains

Before diving into the solutions, it’s important to identify the types of stains that commonly occur in pools. Different stains have different causes, and knowing what type you’re dealing with will help you choose the best removal method.

1. Metal Stains (Iron, Copper, and Manganese)

Metal stains are common in pools with high levels of metals like iron, copper, and manganese. These metals can enter the pool water through source water, algaecides, or even metal pool equipment. When metal levels are too high, they can react with chlorine or other chemicals in the pool and cause stains, typically appearing as brown, blue, or black marks on the pool surface.

• Iron: Typically causes brown or rusty stains.

• Copper: Often leads to blue or green stains.

• Manganese: Can cause black or dark purple stains.

2. Organic Stains (Algae, Leaves, and Debris)

Organic stains are often caused by algae, leaves, or other organic matter that falls into the pool. These stains usually appear as green or brown marks on the pool floor or walls. Organic stains are particularly common in areas with heavy vegetation or pools that have not been properly maintained.

• Algae: Green stains or patches of slime on the walls and floor.

• Debris: Leaves, twigs, or other organic material can leave brown or green stains if not removed quickly.

3. Chalk or Calcium Hardness Stains

Calcium hardness stains are caused by high levels of calcium in the pool water, often due to hard water. When calcium levels are too high, the water becomes saturated with calcium, which can deposit on the pool surfaces, causing white, cloudy, or flaky stains, particularly on the waterline.

• How to Spot It: These stains typically appear as white, chalky deposits that can build up around the waterline.

4. Sunblock and Oil Stains

Sunblock, lotions, and oils from swimmers can leave stains on your pool’s surfaces. These stains are typically oily and can create dark or cloudy patches on the pool floor or walls, particularly around areas where swimmers tend to linger.

How to Remove Different Types of Pool Stains

Once you’ve identified the type of stain in your pool, it’s time to tackle it. Each stain requires a different cleaning approach. Below are expert tips on how to remove each type of pool stain effectively.

1. Removing Metal Stains

If your pool has metal stains caused by high levels of iron, copper, or manganese, there are a few ways to tackle them:

Use a Metal Stain Remover

• What You Need: A pool metal stain remover (often available in liquid or powder form).

• How to Use:

  1. Test your pool’s metal levels using a reliable pool test kit.

  2. If the metal levels are high, apply a metal stain remover to the affected areas following the manufacturer’s instructions.

  3. Run the pool filter to circulate the chemical and allow it to work on the stains.

  4. Vacuum up any residue once the stain is gone.

Try Ascorbic Acid (Vitamin C)

• What You Need: Vitamin C tablets or powder.

• How to Use:

  1. Place the ascorbic acid directly on the stained area.

  2. Let it sit for a few minutes to break down the stain.

  3. Scrub the area gently with a soft brush to remove the stain.

• Tip: Always test any new products on a small, inconspicuous area before applying them to the entire pool surface.

2. Removing Organic Stains

Organic stains are relatively easy to remove with the right approach. Here’s how you can handle them:

Shocking the Pool

• What You Need: Pool shock (preferably a non-chlorine shock or chlorine shock, depending on the severity of the stains).

• How to Use:

  1. Shock your pool by adding a high dose of chlorine (or non-chlorine shock).

  2. Run the filter and allow the chemicals to circulate through the pool.

  3. Scrub the stained areas with a pool brush to loosen the algae or organic material.

  4. Clean the pool’s filter to remove the contaminants.

Using an Algaecide

• What You Need: Algaecide that is compatible with your pool type.

• How to Use:

  1. If algae are present, add the appropriate algaecide to the water to target the algae.

  2. Follow the manufacturer's instructions to add the correct dosage.

  3. Scrub the affected areas and allow the filter to remove the excess algae.

• Tip: Regularly vacuum and brush the pool to prevent future organic build-up.

3. Removing Calcium or Chalk Stains

High calcium levels can cause stubborn chalky stains, but with the right steps, you can clear them up.

Use a Calcium Hardness Reducer

• What You Need: Calcium hardness reducer (usually in liquid form).

• How to Use:

  1. Add the recommended amount of calcium hardness reducer to your pool.

  2. Allow the pool to circulate for 24 hours.

  3. Test the calcium hardness and adjust accordingly.

Use a Pool Cleaner or Acid Wash

• What You Need: Pool cleaner or diluted muriatic acid.

• How to Use:

  1. Dilute the muriatic acid with water (always follow safety instructions when handling acid).

  2. Apply the diluted acid to the stained areas, and allow it to sit for a few minutes.

  3. Use a soft brush to scrub the area gently, then rinse thoroughly with water.

• Tip: Acid washing should be done sparingly and only as a last resort to prevent damaging the pool surface.

4. Removing Oil and Sunblock Stains

Sunblock and oils can leave greasy stains, but they can be removed with the following methods:

Use a Pool Surface Cleaner

• What You Need: A pool surface cleaner or degreaser.

• How to Use:

  1. Apply the cleaner directly to the stained areas.

  2. Let it sit for a few minutes to break down the oils.

  3. Scrub the stains gently with a pool brush and rinse with clean water.

Try a Baking Soda Paste

• What You Need: Baking soda and water.

• How to Use:

  1. Make a paste using baking soda and a small amount of water.

  2. Apply the paste to the stained area and scrub with a soft brush.

  3. Rinse the area with clean water.

• Tip: Regularly clean your pool filter to prevent oils and contaminants from building up again.

Preventing Pool Stains in the Future

Once you’ve removed the stains, it’s important to take steps to prevent them from reoccurring. Here are some tips to keep your pool surfaces clean:

1. Maintain Balanced Water Chemistry

Consistently test and balance your pool water to prevent staining caused by imbalanced pH, calcium, and chlorine levels. Regular testing is key to maintaining clean, stain-free surfaces.

2. Use a Pool Cover

Covering your pool when it’s not in use helps prevent debris, leaves, and contaminants from entering the water. This will reduce the likelihood of organic stains and minimize the amount of cleaning needed.

3. Regularly Clean Your Pool

Regular maintenance, including vacuuming, skimming debris, and brushing the walls and floor, can prevent stains from building up. A clean pool is less likely to develop discoloration over time.

4. Consider Installing a Pool Water Softener

If you live in an area with hard water, a pool water softener can help reduce calcium buildup, preventing chalky stains and cloudy water.