Where is it at? And what do you mean dull? No light on the cool end? The UVB is fine for wattage you dont want anything stronger for a 40+ gallon tank unless your using a tank that is really tall like higher than 24" -- you can use a regular household bulb low wattage like 40 or 60 watt or a LED bulb - you dont want your ambient temps on the cool side over 85 --Hi at the moment i have a arcadia 12% desert 24w uvb can i up the wattage it seems a bit dull on the cool end or can i move it over???
I would try and get it closer to your basking side or in the middle of the tank and set up a second basking areaIt is 22" long i have put it more on basking side should i just move it over???