I've been wondering why I can't get a uvb reading from my bulb unless I hold the reader card directly under the bulb rather than down at the level my Uro would be. I don't want to have to worry about MBD, and when searching info today. I came across this info from deerfernfarms saying they don't recommend uvb lighting anymore and just use the vit d3 powder: "While many if not most sites still recommend the use of a UVB producing Mercury Vapor basking bulb, after many years of trials, we no longer feel these are a good choice for your reptile. UVB initiates the conversion of vit. D3 precursor into active vitamin D3, and in theory these bulbs produce enough UVB to stimulate this reaction. However we have been measuring output from about every bulb ever put on the market over the years and the vast majority put out far too little UVB to be useful in this process. Additionally both ourselves, colleagues and several Zoo's have noticed adverse effects form using these bulbs including basking avoidance to eye and skin issues. Many of us now choose to simply add vit. D3 to the diet and dispense with the bulbs. We spend 4 years rearing half each year's offspring under UVB lights and half on non-UV lights but with D3 supplementation in the food and tracked their growth rates. Those without exposure to UV bulbs did every bit as well as those reared under Mercury Vapor bulbs. When we noticed our Chuckwallas in particular consistently refused to bask under the Mercury Vapor bulbs in 2009, we decided to finally pull all the UV bulbs in the building and replace them with high quality (yet inexpensive) clear white Infra-Red bulbs. We've had no signs of hypo or hyper D3 issues and have been happy with the decision. All that said, if you can give your Uromastyx access to true unfiltered sunlight, it is beneficial. Uromastyx do detect the difference between normal "man made" light and sunlight and are unmistakably attracted to sunlight. All things being equal, Uromastyx raised outdoors in unfiltered sunlight tend to be brighter pigmented and sunlight is no doubt the best and safest UV source." I'm a bit confused as to what to do? I currently already do use the vit d3 powder so should I not worry about the uvb bulbs power and just keep up with the supplement powder and call it good?