Merrill said - Most Tritons last one and a half to two years. The spectrum of Triton tubes follows the "Chlorophyll curve" and that is why they are effective in growing aquatic plants as well as corals. ----no question. I just installed a 20w triton to complement 2 trichlors and a vitalite. The plants have really responded! I can't believe it! I too have to order it special through my FAVORITE lfs.