The problem is that im using a box with 30'x16'x12' inches dimensions. so I already have lights in the top of the box in the form of cfls, however im using that tube fixture to run up the sides of my box so that it can help not only pump more lumens inside of the box but also help light exposure get to the areas of the plants which are being slightly shaded by my top set of leaves.I tend to disagree, removing the cover/ diffuser allows every single lumen access to those leaves, and baby those plants never get enough light, most growers raise the lights come watering time, why not you...? some even smear some Vaseline on the pins to avoid any humidity, for a tighter more positive join, avoid the 13w tube... standard T5 grow is the 54w tube, thats if you want yield, with 6-8 tubes on a rack, hung from chains adjusted daily