Stains and Discoloration in a Vinyl Liner Pool


When your pool and backyard is as post card pretty as this pool, the last thing you want are stains on your pool’s vinyl liner.

Above ground or inground pools both use vinyl liners, and are susceptible to staining from minerals, organic materials and chemical damage.

For all of you vinyl liner pool owners, here’s how to identify, treat and prevent staining of your vinyl liner pool.


One advantage of vinyl pool liners is that the slick surface often reduces mineral staining. It’s not uncommon to see the pool stains more pronounced on plastic and metal items in the pool, such as on your ladders, steps and pool lights.

Vinyl liners also can stain in localized areas or spread throughout the pool surfaces. It can be just one small spot or only at the waterline, on on the pool steps. Size, color, location and any “behavior” of the pool stain can be helpful in identifying the source or cause of the stains.

copper-test-stripsTesting your pool water for mineral content can also be helpful to identify pool stains. Test your water for iron, manganese or copper. carries copper test strips available in our water test kit department.

Mineral Pool Stains

Mineral pool stains can be every color of the rainbow, but a few are more common. Blue/Green stains are usually from too much copper in the water. Iron pool staining can be brown, red or a yellow / orange color. Calcium or sodium salts can leave whitish deposits on your pool liner.

For stains on a horizontal surface, you can test the surface for mineral staining by using a small amount of acid on the stain. Place a vitamin C tablet (ascorbic acid) on the stain for a short time period. You can also use pH decreaser (sodium bisulfate) placed into a sock. If the stain lightens considerably, you have a mineral stain on your hands.

Organic Pool Stains

Organic stains come from dead algae, or other small animals, or from the tannins contained in leaves and plant debris. Organic stains can stain a range of colors from yellow to brown to black. These stains normally occur after a long winter or after a big thunderstorm.

Organic chemicals respond to chlorine applied directly on the surface. Sometimes just shocking the pool will lighten or remove organic pool staining. Place a chlorine tablet on a stained area for just a few minutes. If the stain lightens, then you have an organic pool stain.

Chemical Damage

Fading can occur from the sun naturally over time, or vinyl liners can become “bleached” from high chlorine or low pH levels. Broadcasting granular chemicals into a vinyl liner pool is generally a no-no, instead pre-dissolve into a bucket of water first. Chemical or UV damage is not considered a stain on the pool surface and is generally not treatable.

jacks magic stain-ID kit helps you determine which steps to take next to remove your pool stainsUnsure of which type of vinyl pool stain you have? The Jack’s Magic Stain ID kit helps you determine what the next best steps would be to remove your particular type of pool stain.


To begin treating a pool stain, the first step to take (after identification) is to balance your pool water chemistry. In some cases, merely adjusting the pH, Alkalinity and Calcium Hardness levels can lighten or remove some types of pool stains. Use a fresh pool test kit or test strips, and adjust your pH to 7.5 – Alkalinity to 100 – and Calcium Hardness to 200.

Mineral Pool Stainspool chemicals for stain removal and prevention

Generally speaking, mineral pool stains respond best to a treatment with acids. Plaster pools may be acid washed, or a stain-master used for localized rust stains – but you can’t acid wash a vinyl liner pool, can you?

Vinyl pool stains can be removed with acidic stain removal products like Stain Free, or A+ Stain Remover, or Jack’s Magic Blue Stuff for vinyl liners. If the stain is on your vinyl pool steps, try Jack’s Magic Step Stuff.

Organic Pool Stains

Generally speaking, organic pool stains respond best to a treatment with oxidizers. For plastered pools, you can just dump powdered shock right onto the bio-stain, and watch it instantly disappear, but you can’t do that with a vinyl liner pool, can you?

Organic pool stains can deposit themselves only around the main drain, on the steps or corners of the pool. Balance the chemistry, add super pool shock, according to directions. If that doesn’t remove the organic stains, try one of the products listed above. Safe for vinyl liners, and they work for both mineral and organic pool stains.


Keeping your pool water balanced and the pool clean, especially during the off-season, is important for keeping your pool stain free. If your pool water comes from a well, it may contain high metals and minerals. And of course, always use stainless steel screws on your ladders, lights, steps and faceplates – and ban the use of hair ‘bobby pins’ in the pool.vinyl-pool-stain-prevention-chemicals

To control pool stains from metals and minerals, use Jack’s Magic Purple Stuff or MetalFree. Our own Super Stain Away is very popular, and for severe mineral and metal issues, CuLator will reduce levels.

These stain prevention pool chemicals control pool staining by making it difficult for minerals in the water to precipitate out of solution, where it can stain your vinyl liner, steps or ladders.

No one likes stains in their vinyl pool! If you have been battling pool stains, and are finding it difficult to resolve, give our pool stain experts a call here at 800-288-7946!



Davy Merino
InTheSwim Blog Editor


Stains and Discoloration in a Vinyl Liner Pool — 57 Comments

  1. Pingback: No Drain Pool Acid Wash | InTheSwim Pool Blog

  2. I have an above ground pool and after the Thomas Fire I went to vacuum my pool to remove the dirt and ash from the fire it left dirt looking stains in SEVERAL spots on the bottom.I have tried brushing and with A LOT of work will come out. Is there a easier way?

    • Hi John, vinyl is a porous material and can soak up certain types of stains, but don’t lose hope, as many stains can be removed in a vinyl pool. For your particular case of fire ash and such, I would try using A+ Stain Remover, ascorbic acid. Follow instructions, including pre-use water chemistry, treatment and filtering. In most cases, no scrubbing is needed. If the water is cold now, it can be more effective to wait for water temps of 75 and above.

  3. I have my liner tearing along the water line. There is a brown ring at the waterline on the sides of the pool that get direct sunlight.
    I’m going to have to get a new liner. But would like to know what his cause this so it doesn’t happen again.

    • Hi Cindy, direct sunlight does bleach vinyl over many years, and can pull out some plasticisers, making vinyl more brittle. A shade sail or awning could be strategically placed to block sun along a wall or end of a pool, I suppose. Pool Chemistry is another biggie, high chlorine and low pH, alkalinity and calcium levels can make a liner very brittle. Both sun and chemicals can cause the liner to tear horizontally, or snap as I like to say. Another cause of snap rips are when a liner is a bit too small, and is stretched a bit too much near the top, or if the sand bottom contours change, causing a liner to slip. The brown ring at the waterline could be pollution, or from winter water levels, or airborne dust and oils. Using enzymes regularly, and at closing is a good way to combat it. You can also clean the pool water line a few times per summer, using Tile & Vinyl Cleaner, to gently scrub off any grunge. I ‘suppose’ you could also condition it with a spa cover conditioner, which IS a vinyl conditioner. I’ve never heard of, nor have I ever tried to ‘condition’ a vinyl liner tile line, like a dashboard (or vinyl spa cover), but I suppose you could, it should add flexibility and UV resistance, but I wouldn’t do it too often – just to keep strange chemicals out of the pool.

  4. I have an above ground pool. Some of the rubber playground mulch (recycled tire pieces) from my kids’ play area got over by and under the edge of the pool. It has left brownish stains on the liner. Some stains also seem to have bled through to the inside of the liner. I had issues with high pH all summer long. The water is very hard in my region. Any thoughts on how to get these rubber stains off the liner?

    • Hi Mike, could be difficult, sounds as if the stain bled through from underneath. You could cover it with a vinyl patch of the same color or pattern, if you have saved scraps. Glue it on with vinyl patch glue or EZ Patch 28 sealant, to hide the stain. However, you could try some things first, get a $5 bottle of vitamin tablets, grind up a handful in the coffee grinder, or crush them, to a rough powder. Hold a 1.5″ or 1″ PVC pipe (or plastic pipe) over the stain, and pour the stuff in and let it settle. Hold the pipe still for about 1 minute, then remove and brush the area by getting in the pool with a sturdy scrub brush, and scrubbing it underwater (with mask or goggles). Inspect it while under there – if it worked mostly, repeat. If it did nothing, try again with about 3 tablespoons of pH decreaser, or pH down (sodium bisulfate), repeating the entire process. You could also make a stain sock, adding either a vitamin C product like A+ Stain remover, or EZ Stain remover, or ph decreaser...

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