Solis Tek Metal Halide Digital Lamp 600W MH 6K BLUE optic foliar earthworm castings provide nutrients in earthworm castings provide nutrients in forms that are immediately available to plant roots while also feeding the living biology of the growing medium for sustained nutritional release over time HydroMaster Digital testers make monitoring water easier than ever by reading the levels that matter most and providing accurate readings that you can depend on Our special low iron glass allows for more UV spectrums to get to your plants and flowers Pulse start Digital Lamps Featuring Low Iron (Low E) glass for enhanced UVA and UVB penetration to your plants for higher quality and yield