How do I remove rust stains from my pool?

Use a pool stain remover designed for rust, and test the water for metals to prevent further staining.

What Causes Rust Stains in Pools?

Rust stains in pools usually come from one of three things:

1. Metal objects left in the pool: Coins, hairpins, screws, or toys made of metal can sink and sit on the surface, releasing iron that leaves a stain.

2. High iron content in the water: If you're filling your pool from a well or have an older plumbing system, rust can be coming from the water itself.

3. Corrosion from pool equipment: Rusted parts from ladders, light fixtures, or pipes can slowly leak iron into the pool.

Knowing the source helps you stop the problem at its root. If you treat the stain but don't address what's causing it, the rust will just come back.

How to Identify a Rust Stain

Not all stains in a pool are rust. You might be dealing with organic material (like leaves or algae) or mineral deposits. Here's how to tell:

• Color: Rust stains are typically reddish-brown or orange.

• Location: Often found near metal objects, fittings, or random spots where a metal item sat.

• Texture: Rust stains don’t brush off easily like algae. If it feels smooth and doesn’t budge, it’s likely rust.

Step-by-Step: Removing Rust Stains from Your Pool

Once you know it's rust, here's how to get rid of it effectively. There are both DIY and chemical options. Pick the one that fits your comfort level and budget.

Option 1: Vitamin C Tablets (Ascorbic Acid)

This is the easiest and most pool-friendly method, especially for small stains.

Steps:

1. Get a few vitamin C tablets.

2. Rub the tablet directly on the stain.

3. Wait a few minutes. If the stain lightens or disappears, it’s rust.

4. Keep rubbing until the stain is gone.

This method is cheap and works well for small surface stains. It’s safe for vinyl and plaster pools.

Option 2: Ascorbic Acid Treatment for Larger Stains

For larger or widespread rust stains, you’ll need powdered ascorbic acid.

Steps:

1. Lower chlorine levels to near zero.

2. Adjust pH to around 7.2.

3. Turn off the pool pump.

4. Sprinkle ascorbic acid over the stained areas.

5. Let it sit for 24 hours.

6. Brush the area gently and turn the pump back on.

7. Rebalance water chemistry slowly.

Ascorbic acid lifts the iron particles from the pool surface and helps them dissolve into the water so they can be filtered out.

Option 3: Metal Sequestrants

Sequestrants don’t remove stains, but they help prevent new ones. They bind with iron and other metals, keeping them in solution so they don’t settle and stain.

Use these after stain removal to keep your water clear of rust-forming metals. Add them weekly or after heavy rains.

Option 4: Acid Washing (For Concrete Pools Only)

If stains are deep and stubborn, you may need to acid wash the pool. This strips away a thin layer of plaster or concrete, removing embedded stains.

Warning: This is a harsh method and should only be done by professionals or experienced DIYers. It shortens the life of your pool surface if done too often.

Tips to Prevent Rust Stains

Once you've cleaned your pool, it's smart to prevent the issue from happening again. Here’s how:

• Don’t leave metal objects in the pool.

• Use a metal sequestrant regularly.

• Check and replace rusty pool equipment.

• Test fill water for metals, especially if using well water.

• Keep water chemistry balanced (especially pH and chlorine levels).

Prevention saves you time, money, and frustration. A few minutes of maintenance each week can make a huge difference.

When to Call a Pro

If you've tried everything and the stains keep returning, it may be time to call in a professional pool cleaner. They can test for hidden sources of iron, inspect your equipment, and use advanced tools to treat the stains.

Some pool companies offer specialized rust stain removal services, and while they cost more upfront, they can save you from repeated DIY efforts that don't stick.