If you want to use sand you should be using washed play sand... as calci sand can be very very dangerous. Im speaking from two very bad experiences i had using it, One was a baby beardie and the other was an adult beardie. Both got impacted because the "calcium" sand turns into a concrete like substance when wet so imagine what its like in a wet stomach. The baby beardie was on it for two minutes or so and died within a week while the adult lived for two years, when i got him he was pretty old and had bad care before but didnt die of old age and instead died of impaction even though hes an adult. The 100 bulb should be good but you'll want to change the uvb to a linear/tube light T5 HO 10.0 or one of the Arcadia tube lights. Other than the setup he does look very healthy, and once you get the correct lights and substrate he should be eating again. If not i'd get him checked out by a vet for impaction.