GREEN BRIGHTY NEUTRAL K is a liquid fertilizer for supplying potassium to a planted aquarium. When potassium is insufficient, the photosynthesis activity and growth of aquatic plants are affected and this can cause yellowing and bleaching of leaves as well as lower resistance to algae. Daily application of GREEN BRIGHTY NEUTRAL K to the aquarium eliminates these problems caused by potassium deficiency and promotes growth of aquatic plants. This product does not cause a rise in pH and carbonate hardness (KH). It is ideal for supplying potassium to aquatic plants that do not prefer high pH and KH environments. *Although the color of the liquid might slightly change due to a loss of the pigment as time advances, it can be used as it is because the principal ingredients do NOT change.