Ok I'm using a Arcadia D3 all in one basking bulb says on the box 80W 11+ uvb also says its a heat bulb, is this ok for a baby bearded dragon in a 4feet viv with a heat mat aswell under the viv temps are all correct using thermo gun and wired thermometer
That's a pretty close range MVB. It will produce adequate UVB at around 8-10'' or so but won't be powerful enough beyond that. It has to be mounted in that range for proper UVB exposure so if it isn't producing enough heat then it will need supplemental lighting as well. It also has a relatively narrow beam so it won't produce much UVB outside of the basking area so it may be better to use an Arcadia T5 22'' UVB light in a tank that big.