ATI Purple Plus T5 High-Output Fluorescent bulb combines the properties of a full spectrum bulb with strong red and blue components producing a bulb with excellent color-rendition that works very well for bringing out the pinks, purples and reds in an aquarium. Recommended Use: in combination with at least 2 or more other T5 bulbs like the Blue Plus and Aquablue Special. Not recommended as a stand-alone bulb.