I placed the unit I purchased directly on my tank yesterday, and the shadows were horrible. Areas of my rock completely dark. However when I raised the light to the level where my T5's were it made a big difference. Too close to the water creates a spot light effect? If you had your light that low, try raising it a few inches and see if that helps. I wouldn't say it is the equivalent to a single T5, just not sure if it can replace my 4 bulb T5 with 2 ATI Blue Plus and 2 ATI Blue Special.