Getting stains out of a saltwater pool often requires identifying the cause and using specific treatments. One common cause of stains is dissolved metals in the water, which can precipitate out and stick to pool surfaces.
Removing Metal Stains
Based on the provided reference, a multi-step process can be effective for removing stains caused by dissolved metals:
- Make the Pool Alkaline: Adjust the water chemistry to make it alkaline (increase the pH). This helps precipitate the dissolved metals out of the water.
- Add Flocculant: Introduce a floccing agent (flocc) to the water. Flocc causes the fine metal particles that have precipitated out to clump together into larger masses that can be easily removed.
- Allow Settling: Leave the pool water undisturbed, typically overnight, to allow the flocced metal particles to settle to the bottom.
- Vacuum to Waste: Carefully vacuum the settled material from the pool floor. It is crucial to vacuum to waste rather than through the filter. Vacuuming to waste bypasses the filter and sends the dirty water out of the pool, preventing the metals from being recirculated back into the water.
- Balance Water Chemistry: After vacuuming, test and re-balance your pool's pH, alkalinity, and calcium hardness levels.
- Add Metal Solution: Add a metal sequestrant or solution, such as 1 Litre of Lo-Chlor Metal Solution (as mentioned in the reference), to the water. This type of product helps to chemically lock up any remaining dissolved metals, preventing them from staining surfaces in the future.
This process is estimated to remove about 70% of dissolved metals. For saltwater pools, this treatment may need to be repeated every six months to manage metal levels and prevent recurring stains.
Understanding the Cause
- Metals: Stains can appear in various colors (brown, rust, green, black) depending on the type of metal present (e.g., iron, copper, manganese). Metals can enter the pool water from source water, corroding metal equipment (like heaters), or even from algaecides containing copper.
- Organic Matter: Leaves, berries, and other organic debris left on the pool surface can also cause stains, often brown or reddish in color. These typically require different treatment methods, such as enzymatic cleaners or targeted stain removers.
Addressing the source of the metals is key to long-term stain prevention in saltwater pools.
