What are all of your temperatures reading right now?

What type of thermometer are you using to read them- dial, stick on, digital. How are you measuring your basking spot temperature?

The basking spot which is the surface area of the rock or whatever object you have for basking should be between 115F and 130F. I have mine at 120F. The ambiant temp or air temp around the basking spot should be between 95F-100F. The cool side should be in the high 70s to mid 80s. The night temp can drop to the extremes of 50F but should not exceed 60F. It is not nessesary to make the temps drop that low at night. Things like a ceiling fan or an open window can increase heat loss dramticly. A heat gradient means that it should be hot on the basking side and slowly decreases temp as you reach the cool side. usally just having the warm side and cool side at proper temps creates a heat gradient. Under-the-tank heaters are a bad idea because you have now way of controlling the heat they emitt and the effects could be similar to a hot rock. If you have a screen top cage its a good idea to cover the screen with cardboard or wood the combat escaping heat.

There is no real proof that UV-B lighting is essential for reptiles but it is widely agreed that uros should have it. The bulb that I use is the Repti-sun 5.0 desert bulb. The bulb has to be within 12" of the uro or it will not have any effect. So seeing as your cage is 20" you will have to raise the basking spot considerably. UV-A is just light.

Most people who work with uros agree that birdseed is a good subtrate for them. There is no risk of impaction and it is helthy for the uro to eat. The birdseed must have no sunflower seeds in it. Millet works the best. Impaction is where something (ussaly sand) blocks the intestinal tract.

A very good therometer to use for the air temps is the acu-right ditgital therometer sold at wal-mart for $15. To check the basking temp you need a temp gun. Those run for about $25. I bought mine from doug dix at www.deerfernfarms.com.

"The night temp can drop to the extremes of 50F but should not exceed 60F."

I do not agree with this statement at all.

The chance of respiratory infections increase with extreme night time drops and is even greater if the humidity level is elevated.

While a ’down time’ is beneficial, temperatures should never be allowed to drop to the extremes of 50. I would shoot for temps no lower than 70 and provide supplemental night time heat if temps even get close to 65.

If you are assuming night time temperatures naturally drop this low in the wild, then realize that uromastyx that use underground burrow sleeping chambers are insulated from this outside ambient temperature. From studies on Aegyptia, we know that the sleeping chamber only dropped to a low of 69F during the harshest winter month and that ‘low’ monthly summer burrows temps averaged 86.76F and highs averaged 90.52F. Four of nine of the low months exceeded 90F and six of nine exceeded 90F in the high average. The four winter months averaged a low of 70F and a high of 74.84F.

I try not to allow my enclosures to drop below 68F. Due to increasing data on uromastyx, this spring I will change my thinking on night time temps (from what I have done in the past) and shoot for summer night time temps between 78-83F -only dropping down to 68F during the winter months. I am still waiting on additional year around burrow temperatures from someone I know who has been studying this data. Once I have this information, I will decide on my exact summer/winter night time temperatures. Depending on species, natural climate, and type of sleeping burrow, I will adjust these temps and probably run some of my enclosures towards the low end while others will be towards the higher end.