Twiz the plastic legs (which are sold separate) are adjustable and they do hook over the edge. I would not want to use this fixture without them. The warpage to my tank came from the heat of initially using a T5 strip (roughly 58w) and laying it directly on top of the tank. That caused some heat warpage. I am totally happy with the Coralife system I use now. It provides adaquate lighting for a good array of live plants, and it looks great. If you go online and look at the Coralife fixtures, and look at the adjustable leg assessories you will get a good idea how it all works.
