Aqua One AquaLume LED Light Unit 18cm 7W (59157) Aqua One AquaLume LED Lights features a low profile and space saving design that provides optimal lighting conditions to suit your frameless aquarium. Legend:PAR (Photosynthetically Active Radiation) is an important starting point to estimate light energy for photosynthetic aquarium needs. It is the spectral range of solar light from 400 to 700 nanometres that is generally accepted as required by plants and other single-celled algae that live in tissue of animals such as coral, clams and anemones.Kelvin Rating in lighting assists in defining the colour temperature of a bulb Colour temperatures above 55000K are cooler colours (such as green-blue). In comparison, lower colour temperatures such as 30000K are warmer colours (such as yellow-red). LUX Rating is a measure of the intensity of light 1 LUX = 1 Lumen per metre2. Notes, Hints & Tips: All species of fish and plants have specific requirements for their care. Please seek advice from your Aqua Oneretailer for correct care requirements. It is recommended that the light unit is turned off for at least 8 hours per day to allow the fish a proper night period.More than 10 hours of full light daily can encourage excessive algae growth.