Uromastyx urates are hard/crystalline

Question
My uromastyx's urates are hard - almost rocklike - is this normal?

I have a uro who is approximately 9 mo old and 7 inches long nose to tail.  I
don't know his sub-species.  Over the past couple of days I noticed that there
were far fewer little poops than usual.  I felt his abdomen and there was a
lump - I worried about impaction.  Before making a doctor's appt, though, I
put him into a pan of warm water to see if he would poo (I have some beardies
who *only* poop in the bath).  He did, and I dried him off thoroughly to
prevent tail rot, etc.  I examined his business and while the poo itself was soft
the urates were almost calcified!  They were actually crystalline.  I know that
uros don't drink at all, and they have interesting ways of metabolizing water
and excreting things in ways which don't waste water (like the salts from the
nostrils) but I was wondering if hard urates is one of those things.

Answer
Hello Melissa,

No, it is not normal for their urates to be that hard.  They should be much softer.  
What foods are you feeding?
What are the temperatures that you are keeping him at, & what type of thermomter are you using?  A round stick on type, a digital probe or a temp gun?
Are you using a UVB light?

Tracie