Understanding Metals in Swimming Pools
Iron and copper are two of the most common dissolved metals found in swimming pools. They often enter the water through well water, municipal water supplies, corroding heaters, plumbing, mineral systems, or copper-based algaecides. Even when the water looks clear, dissolved metals can cause staining once chlorine levels increase or the pH rises.
Common Signs of Metal Problems
- Brown, orange, or rust-colored stains often indicate iron.
- Blue-green or black stains may indicate copper.
- Copper can also contribute to green-tinted blonde hair.
- Clear water can still contain dissolved metals.
Managing Metals
- Keep pH within the recommended range.
- Use a quality sequestrant when metals are present.
- Avoid unnecessary copper-based products.
- Consider pre-filtering well water before filling the pool.
- Investigate heater corrosion if copper levels continue to increase.
Why Testing Matters
Testing helps determine whether stains are caused by metals instead of algae or dirt. Correct identification prevents unnecessary chemical treatments and helps protect pool surfaces and equipment.
Important Notes
- Sequestrants keep metals dissolved but do not remove them from the water.
- Large water replacements may require additional sequestrant.
- Always confirm stain type before beginning stain-removal treatments.