The Coralife T5's would never reach the bottom of the tank with useable light. They are also crap quality. I used to carry them in my store. The original ones I brought in are still running. Every unit after about 2006 crapped out between 2 days and 6 months after purchase. Very cheaply made fixtures. Switched to Current USA and had the same problem. They should call their company Current China. That's where all their stuff is made. Unfortunately, there is no middle ground with T5's. It's either brutally expensive but well made, or affordable to non millionaires but junk.