Having a pool means keeping a close eye on the chemical composition of the water. Testing for pH, total chlorine and calcium hardness become part of your routine weekly maintenance. Occasionally, problems develop that cause discoloration because of algae or metals in the water. Copper can cause greenish water, and iron can turn water brown or greenish. Manganese can produce black stains on pool walls. To clean metals out of swimming pool water requires the addition of a pool sequestrant to keep the metals in solution so that they can be filtered out of the water.
Things You'll Need
Pool test kit
Test the pool water to determine if the water chemistry is out of balance.
Scrub walls and the bottom of the pool vigorously with a brush to remove stains and metal particles.
Add a metal sequestrant to the pool water according to package directions.
Run the filter for 48 hours to allow it to remove the metal from the water.
Remove and rinse the filter 3 or 4 times during the filtering process to eliminate metal particles from washing back into the pool.
Add chlorine to shock the pool. Walk around the edge of the pool as you add the liquid shock to the water. Avoid splashing the liquid on clothing. It will bleach color from fabric.
Filter the water for 24 hours.
Test pH again and adjust with sodium carbonate to increase alkalinity, for a higher pH, or muriatic acid to increase acidity, for a lower pH.
Corrosion from metal parts in heaters can cause contamination and staining of pool water, according to Pool Center. This is common in older equipment with copper or iron pipes. Check your pool equipment and replace parts that show rust damage.
According to Par Pool & Spa , you should keep your pool pH in the range of 7.4 to 7.6 to avoid corrosion of pool equipment parts.
In order to test the pool water to see if metals are the problem, Scott Forbes recommends buying a vitamin C tablet and rubbing it on the stain on the pool wall. If the stain fades, it’s from a metal problem. If it remains, the stain is probably organic and needs a different type of treatment.
Many pool water algaecides contain copper which may cause a metals problem.
For a stubborn metal problem in pool water, take a sample to a pool professional for testing to determine what the metal is and how best to treat it.
Well water is often naturally high in mineral content, usually iron and manganese, according to Pool and Spa. If you use well water to fill your swimming pool, pay particular attention to mineral discoloration and treat regularly