Be confident in your purchase we're an Authorized ATI Dealer. How cool is that?!?!? ATI has been some of the most sought after bulbs in the reef aquarium hobby. With their bright crisp colors, ATI are our number one choice when it comes to T5 bulbs. With ATI bulbs you can use a single color on its own or you can mix and match to make the ultimate spectrum. ATI Purple Plus T5 High-Output Fluorescent bulbs combine the properties of a full spectrum bulb with strong red and blue components which brings 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.