How to Identify and Get Rid of Pool Stains For Good

Pool stains are the ultimate party crashers.

They show up uninvited, ruin the vibe, and leave you wondering how something so small can be so annoying.

Don’t let those stubborn spots steal your sunshine. Whether you’re battling chalky scale, stubborn organic discoloration, or sneaky metallic spots, we’ll guide you through how to identify, treat, and prevent stains from coming back and putting a mark on your summer fun (literally).

What Causes Pool Stains?

Pool stains are typically caused by three things:
Calcium build up also known as scale
Organic materials like twigs, leaves, or acorns
Metals from copper or iron from pipes, heaters, or even rogue bobby pins

Let’s break down how to treat each one.

What That Pool Stain Color Really Means

Not all pool stains are the same. The color of the stain is a major clue about what caused it, how to get rid of it and prevent it from coming back.

Greenish-Brown Organic debris like leaves, algae, or dirt
Blue-Green Copper from pipes or algaecides
Reddish-Brown Iron contamination, often from rusty pool equipment
Brown, Black, Purple Manganese or decaying organic matter
White or Gray Calcium scale buildup

Determining What Kind Of Pool Stain You Have

Before you throw your entire chemical kit at a stain, test it with Jack’s Magic Stain ID Kit. Inside the kit, you’ll find sample packets for different stain removers, each designed to react with a specific type of stain.

It tells you exactly what kind of stain you’re dealing with and how to treat it—no guesswork, no wasted product.

How to Remove Calcium and Scale Stains

If your pool has chalky white or greyish deposits, you’re likely dealing with scale. It builds up from high calcium levels and poor water balance.

How to treat it:

• Wet the surface and gently rub with a pumice stone or scale eraser—but only on concrete or tile (never on vinyl).
• Keep the surface wet while scrubbing to avoid scratches.
• For heavy build-up, use a professional-grade scale remover or call in a pro if you’d rather skip arm day.

How to Remove Organic Stains

These stains are usually green or green/brown. They typically appear in the off-season or after storms when Mother Nature decides to throw a pool party without an invite.

How to treat it:

• Balance your water chemistry—especially chlorine and pH levels.
• Remove any debris and vacuum thoroughly.
• Use a chlorine neutralizer to lower chlorine levels to 1 part per million.
• Shock the pool with a granular oxidizer to kill lingering bacteria.
• Scrub the stains and run your pool pump for at least 8 hours.

Maintaining regular cleaning and correct water chemistry goes a long way in preventing and keeping these kinds of stains from returning.

How to Remove Metallic Stains

Metals are probably to blame if your pool has reddish, brown, or bluish-green stains. These sneaky stains often come from metal heaters, pipes, or that one bobby pin you dropped last week.

How to treat it:

• Bring chlorine down to 0 parts per million using a chlorine neutralizer or by adding fresh water.
• Add an algaecide to prevent algae while chlorine levels are down.
• Rub the stains with Vitamin C tablets or ascorbic acid.
• Sprinkle ascorbic acid across the pool surface for large stains.
• Run your pump for at least 30 minutes to circulate.

Follow up with a metal sequestrant like Jack’s Magic The Pink Stuff to keep metals from re-depositing.

Acid Washing Your Pool

If you’ve tried everything and those pesky stains still won’t budge, acid washing might be your last resort. It can get rid of surface stains, but not without its downsides. If you don’t actually figure out what’s causing the stains, they’ll probably just come back.

More importantly, acid is corrosive and will wear down the surface, making it rough to the touch. Before deciding if this heavy duty process is right for your pool, talk with your pool service company. If you do decide to do it, know the risks involved and make sure it is only done after exhausting all your other options.

How to Prevent Pool Stains

Once you’ve tackled the stain, keep stains away for good with these stain prevention tips:

Check water chemistry weekly especially pH, chlorine, and calcium hardness
Skim & vacuum often especially after storms
Use a sequestrant for metal-prone water
Book routine pool maintenance to catch issues early
Skip the wire brushes to avoid gouging or scratching plaster

A little vigilance now keeps your pool sparkling all season.

If you’re just getting your pool opened for the season, make sure to check out the do’s and dont’s of opening your pool for the season. Next we’re breaking down LSI. We’ll be giving you tips and professional insights on keeping your water balanced and pool looking good all season.

When To Resurface Your Pool

When you’ve tried all the tricks and are done dealing with stubborn stains, sometimes the best solution isn’t another treatment—it’s a fresh start.

At Mid America Pool Renovation, we specialize in professional pool resurfacing that makes your pool look brand new.

Let’s bring your backyard back to its prime. Get a free quote to get started.