Chihiros Doctor has 3 preset modes for plants, fish and shrimps.when used in the plant mode it suppresses algae growth and promotes plant growth.The fish and shrimp modes kills pathogenic bacteria in the water without harming beneficial bacteria or livestock.This is the newest Chihiros Doctor is the fourth generation rated for tanks larger than 125L (33G). The Chihiros Doctor is controlled in the mobile app 'My Chihiros' and is enabled by Bluetooth connection.