im not even half way done with this book.. i just got it if your are interested in the historic side this is pretty interesting so far:
http://www.amazon.com/Masters-Disguise-Natural-History-Chameleons/dp/0816026181/ref=pd_sim_b_12
your current regalement seems fine. i use to use the zoomed calcium (which is the one you have) and also the reptivite you have the only difference is the calcium d3 as i used rep-cal brand. the was you are supplementing seems fine to me.
i use this supplementation mention in the video. you can skip to the supplementation part. i believe this video was made by a member on here.
http://www.youtube.com/watch?v=lKTbUaOQ0aA
those are super rare as i believe they are not legal here in the U.S. i saw one at some sketchy pet store he in LA a few years ago it was being kept with bearded dragons. i would love to see if any one has at least one.:D
yeah try the other fixture because sometimes i get the same problem and its usually my fixture. let me know how it goes!:D if that doesn't work i would say return it :D
i would say use a heat bulb...or try putting towels around you container to create insulation (although it won't make an extreme difference if you are using a heat pad) sadly almost everything else costs money:(