Reptile & Amphibian Forums

I have a female veiled chameleon in a 16Lx16Wx30H screen cage if I want the basking spot to be 95 degrees and the rest of the enclosure to be about 80 what mercury vapor bulb wattage should I use? Are the t-rex active uv heat bulbs good?

Your basking spot is good or at least just a few degrees more than I would do , however the rest of the cage is too hot. The basking spot should be about 9-93 the warm side in the 80's but the cool side needs to be mid-high 70's.

It's really hard to say which wattage will work because the temp is affected by the temp and humidity in the room around the cage. The best way to get the right basking temp is to experiment by moving whatever light you do get at varying distances until the surface temp of the basking perch reaches the right level. Use a thermometer with a remote probe or an infrared temp gun to measure the surface temp of the perch NOT the air, as this is most accurate. Pro Exotics has great little temp guns for about $45 that make this SOOO easy.

I agree with the other responders. The wattage depends on how close the light is to the basking spot. You need to be able to vary that distance according to what a good electronic thermometer tells you. The cooler parts of the cage should be in the lows 70s and evgen the hi 60s is fine. But another word of warning: Gary Ferguson of Texas Christian University recently published a paper in Zoo Biology that foundf that too much UVB has deleterious consequences on reproduction in Furcifer pardalis. And the MV bulbs put out even more UVB than the ones he was studying. These bulbs should be so far away from the basking site (at least 2 feet) and at that distance, they're useless for basking. If they're going to double as a basking light you need to restrict them to only a few hours/day or, as I've started doing, covering most of the cage ceiling with transparent Plexiglass so the UVB only shines on one small basking spot. In the rest of the cage the UVB gets blocked out.
Ed

Wow, that study must have been a real blow to the manufacturer. Did he test on other basking species besides chams? It is a wakeup call to hear that you CAN actually overdo the UVB produced indoors. Thanks for the info Ed!