spring pool maintenance

How to Identify the Stains in Your Oasis and How to Remove Them?

In Ask the Pool Experts by Platinum Pools

Calcium stains are not the only spots that you can find in your swimming pool.  Any kind of organic or metallic ingredient is subject to mess up the walls of your oasis if you don’t follow routine maintenance.

The Source of Spots in Your Swimming Pool

There are stains of various colors that commonly appear in swimming pools and identifying the ones you have will guide you in the right direction for their removal.

  • The two main categories of stains are metallic and organic based stains, which come in a variety of colors.
  • These color combinations include greenish brown, bluish red, blue-greenish black, greenish red-brown, pinkish red or black purplish brown.

Filthy backyard swimming pool and patioOrganic Stains and How to Remove Them

Organic stains come from leaves, berries, algae, worms, dead animals or other organic residues if they settle on the surface of the pool. If you don’t remove them quickly, they will sink and begin to decompose at the bottom of the oasis. Fortunately, organic stains can be very easy to remove.

  • Organic spots are usually green, brown or bluish purple – It can be easy to diagnose spots if you can see organic waste (like leaves) sitting on the bottom of the pool.
  • If you suspect that the stain is natural, you can apply a small amount of chlorine directly on it. The stain will likely dissolve with a soft-headed brush.

Try a shock treatment with enzymes together with a hard brush to remove stains.  It can quickly eliminate the greenish-brown spots that accumulate due to organic waste. You can also try an enzyme-based cleaner for your pool. The great thing about natural enzymes is that it will help eliminate organic stains without any scrubbing.  It also helps to break down organic compounds and oils by accelerating chemical reactions that help make the stains practically disappear on their own. After this, scrub thoroughly to make sure you eliminate all residues and oils left.  Another shock treatment method is by using chlorine.  Use enough of the chemical and give a good brush.

  • Test the water to make sure that the pH and alkalinity levels are adequate. pH levels should be between 7.4 and 7.6, and the alkalinity between 100 and 150 ppm (parts per million).

swimming pool surface stainsMetallic Stains

You may wonder how hard stains get into your pool’s surface.  Metals can get into your oasis by transporting it from a water well or corrosion from copper pipes.  Imagine how big a metallic stain can be by just dropping a penny into the pool.

The types of metals that can get into your pool include rust, manganese, iron, and copper. Also, if you detect rusty stains underneath a ladder, you should check if the item has rust.  You should check in areas where there are metals like stairs, drains and under the edge of the pool to see if there is any discoloration. Stains that look reddish brown or very dark are usually related to the metals in the pool water.

  • The metals that commonly cause stains in swimming pools are iron, manganese, and copper. Copper comes from ionizers and corrosion from copper and brass pipes. It causes blotches of blue, green, teal, black or dark purple. The iron comes from the water well and the corrosion from iron pipes and equipment, causing rusty brown, gray or greenish brown spots. Manganese comes from water wells, creating pink, dark brown or dark brown spots. Calcium comes from plaster, grout, mortar or calcium hypochlorite shock and manifests as white crystals.
  • If you have a metal-based stain, it is essential to know precisely what metal causes it to treat it properly.
  • A blue-green copper stain is a common cause of inadequate chemical maintenance. Low pH levels and high chlorine levels can also erode the copper heat exchanger inside the pool heater. Maintaining a proper balance in the water makes it easier to avoid the appearance of metal stains.
  • Determine if the water intake is the problem. If you fill the pool from a water well, test the water directly before filling the pool. If you determine that there is a large number of metals in that water, drain the pool until there is a quarter or half of the water and fill it with softened water. Then, you will have to circulate the water for at least 48 hours and try it again. Repeat the procedure if there is a high concentration of metals.
  • If the water intake is not the problem, metals are likely to enter the pool’s water through corrosion. Check all pool equipment to see if there is corrosion and make sure that no metals are leaking into the pool water.
  • Wash the pool with acid. If a permanent spot develops, you can drain the pool water and wash it with acid if it has a plaster coating. It is not something you can do all the time as it involves scraping a thin layer of plaster from the pool intentionally. To restore the white and shiny surface, you should use an acid wash around every five years.

Use Muriatic Acid and a Scrub Brush to Remove Spots

  • After using the product to remove stains, be sure to give the pool a shock treatment so that there is a sufficient amount of chlorine in the water before it turns green due to an outbreak of algae.

Eliminate metal stains with ascorbic acid. Minerals react better to chemicals and, if you think the stain is related to metals or if the above suggestions for organic stains do not work, try products based on ascorbic acid for swimming pools.

  • Add ascorbic acid to your pool evenly on the surface. Start using 225 g (0.5 pounds) of ascorbic acid for every 38,000 liters (10,000 gallons) of water.
  • Set the filter to “circular” and turn it on. Let the ascorbic acid take effect for half an hour.
  • Check the pool to see if the spots have disappeared. If they are still there, add more ascorbic acid and let the filter circulate the treatment for another half hour. Repeat this procedure until the pool is clean.

You need to monitor the pH, alkalinity and hardness levels to ensure that they are within the appropriate range, which is determined by the size of the pool. You must turn on any automatic chlorinator, chlorine generator, UV system, and ozone generator. Place a new pack of metal eliminator in the pool separator basket or a large metal eliminator package in the pump basket to keep metal levels low and help keep the pool clear of stains along the season.


The best way to avoid any stains in your pool is keeping regular maintenance.  Remember to test the water to maintain a proper pH balance and a proper chemical balance.  If you happen to use water from other sources, you should test it.  Other sources like, for example, water well can contain large amounts of iron, enough to create spots in your swimming pool

  • Perform small shock treatments every week to prevent algae outbreaks.
  • Scrub the bottom of the pool several times a week as a preventive measure.

In-Floor Cleaning SystemBuild Your Pool with An Automatic In-Floor Cleaning System

To make cleaning and maintaining your pool easier, make sure to build your pool with an automatic in-floor cleaning system. How would you like waking up to a clean house every morning without almost any effort on your part? An in-floor cleaning system does just that! Using strategically placed pop-up jets along your pool’s floor and steps, helping to keep your pools surface clean and free from any debris that might collect. An in-floor cleaning system helps to ensure that your pool doesn’t suffer from any organic surface stains as a result of debris sitting in your pool.