Updated: May 15, 2021
Aquatic plants do best under full spectrum light with a Kelvin rating or “color temperature” between 6,500K and 8,000K. Always choose a light source specifically designed for growing aquarium plants; those designed for houseplants have a lower Kelvin rating. HO T5 fluorescent and LED offer the best lighting for aquarium plants today.
watts per gallon” no longer valid. Here’s why: Wattage is a measurement of how much electricity a light consumes, not how much light energy it produces. Light intensity is measured in lumens, not watts, and different sources of light produce different amounts of lumens per watts consumed. For example, a 60 watt incandescent bulb produces fewer lumens than a 54 watt HO T5 lamp, and you would not want to look directly into 60 watts of LED light! Lumens, PAR (photosynthetically active radiation) and PUR (photosynthetically usable radiation) are more meaningful measurements.