I think perhaps return that light and get one which will cover the entire width. Just curious what brand that is. I think it says lucky herp…yes? I do want to caution about using anything other than Arcadia and ReptiSun, unless you have a solarmeter to determine true uvb strength and output. Out of curiousity, I tried one of the better alternative brands (ReptiZoo) and its uvb output was very disappointing. The fixture seems fine, but the bulb is seriously lacking.