I just upgraded my bearded dragon to a 40gal tank I'm currently using a 75w heat bulb and a 10.0 UVB light do I need to get stronger bulbs for a tank this big
Well rather than to just look at the wattage you should measure the temperature in the viv with a thermometer!
Agreed. A variety a factors contribute to the appropriate wattage bulb - ambient house temps, distance from basking spot, type of bulb, wattage, etc. The key is attaining the appropriate temperature gradient in the enclosure and at the basking site. Purchase a digital thermometer with a probe or tempgun (avoid cheap plastic "stick on" thermometers or aquarium strips). You want the area underneath the basking spot to be around 105 degrees F (100-105 usually preferred by adults, 105-110 by juveniles). This is the most important temperature reading because the bearded dragon will spend the bulk of his day basking here and needs these high temps for appropriate metabolic function. In general, the "warm" end, or area around the basking spot, should be ~90 degrees and the cool end can dip down toward room temp (~75-80). These ranges can be more forgiving and variable so long as the basking temp is correct and he has a cooler area of the enclosure to retreat to if he gets too hot for proper thermoregulation. The UVB producing bulb (assuming it's a flourescent bulb) will not be producing much, if any heat. The sole purpose of that bulb is to add lighting and necessary UVB wavelength which the beardie needs for calcium synthesis and general health. You can buy combo UVB/Heat bulbs (special Mercury Vapor Bulbs, [MVB's], such as Zoomed's Powersun bulb... but keeping the heat and UV sources separate is fine as well so long as temps are fine and he can get close enough to the UV bulb.