Blue-green algae growing in natural environments may be composed of numerous species. Because some of them may contain harmful toxins, Spirulina that is intended for human consumption is generally harvested from controlled ponds. In the last few decades, commercial Spirulina systems have developed in many countries, including the United States, Thailand, Taiwan, Japan, Mexico, China, and India. Due to interest in growing Spirulina on a small scale, the first practical startup kits have recently become available for use by small communities and home businesses.