Not only does indicating Silica Gel absorb surrounding moisture, it also changes colors as it does so. The more moisture the Silica Gel absorbs, the less effective it eventually becomes. Once it reaches its saturation point, indicating Silica Gel will turn to a specific color, signaling it should be replaced As the beads takes up moisture, they turns to light blue gradually & When they turn pink, it indicates that the gel need to be replaced or regenerated. In fact, it is mainly used as indicator for the extent of dehumidification and moisture absorption in sealed vessel.