What color should water be just before entering a manganese greensand filter?

The water just before entering a manganese greensand filter should appear slightly pink due to the presence of potassium permanganate, which is used to pre-treat the water in the filtration process. This coloring indicates that the potassium permanganate has been properly dosed and ensures that the greensand filter will effectively oxidize and remove manganese and iron from the water.

When the water appears clear, it suggests that either no treatment has occurred or the potassium permanganate is insufficiently dosed, which could lead to inadequate removal of contaminants. Dark green may indicate excessive potassium permanganate, potentially leading to issues in the filter operation and water chemistry. Brown water typically indicates the presence of suspended solids or high levels of iron or manganese that have not been properly treated, which defeats the purpose of using a greensand filter. These characteristics highlight the importance of the proper preparation and conditioning of water before it enters the filter system.