We put Kastar Ceramic Tile Sealer and other brands of sealant into two transparent containers filled with water with caulking-gun. After 24 hours, we can see that Kastar is insoluble in water and does not fade, because we add silica to the gel to form a dense waterproof layer, so it has a better waterproof effect.

Other brands of sealants are seriously discolored and soluble in water.