Shine Potassium- by Cal Aqua Labs is an essential macro-nutrient required in large quantities. It helps maintain proper function of various processes that regulate plant growth in aquariums. It is often one of the first nutrients to become deficient in a planted fishtank, and thus must be supplied regularly to sustain healthy plant growth. Shine is a highly concentrated mix of Potassium salt and organic acid growth enhancers. It should be added regularly to ensure a continuous supply required for proper plant growth.It is best to ensure that a sufficient supply of Potassium is always present. Begin using Shine one week after setup. Continuous use is highly recommended.