Understanding Iron Stains in Swimming Pools
Iron staining is one of the most common metal problems in residential swimming pools. Iron often enters the water through well water, municipal water supplies, corroding metal components, or contaminated fill water. Once chlorine oxidizes dissolved iron, it can settle onto pool surfaces as yellow, orange, or brown stains.
How to Identify Iron Stains
- Rust-colored, orange, yellow, or tea-colored stains.
- Stains often appear after shocking the pool.
- Vitamin C tablets usually lighten or remove iron stains.
- Water may temporarily discolor after adding chlorine.
Treating Iron Stains
- Confirm metals with a reliable water test.
- Use a quality HEDP-based sequestrant.
- Maintain proper pH and avoid unnecessary chlorine spikes.
- Filter continuously during treatment.
- Identify and eliminate the metal source whenever possible.
Important Notes
- Sequestrants hold metals in solution but do not remove them.
- Ascorbic acid treatments should normally be followed with sequestrant.
- Well water often requires ongoing metal management.