The CuLator Ultra PowerPak 4.0 is the ultimate tool for metal staining prevention. It will efficiently absorb 4.0 ppm worth of metals that include copper, iron, rust, manganese, cobalt, nickel, aluminum, silver and lead from the water before it is allowed to stain. It will not remove existing stains, but it will offer the best protection from new metal stains and discolorations caused by metals. This metal remover pouch will not affect water chemistry or pH, and is phosphate-free and non-toxic. It is compatible with pool surfaces such as vinyl, fiberglass, gunite, screened in pools, pools with stones or bricks for decking or coping. It will work with all sequestrants, algaecides, oxidizers, cleaners, balancers, water enhancers, mineral-based water purification systems, ionizers, ozone, UV, and salt systems. The CuLator Ultra PowerPak 4.0 is best used in systems that draw from wells, large/commercial pools, and pools that have major metal issues for about 30 days or longer if there is a low amount of metals in the water.