my bearded dragon has the runs

Question
okay so my dragon is about 7-8 months old, and around 18 inches. recently hes feces is really runny and smells pretty bad. he lives in a 30-35gal tank and is 105-110 degrees on his basking side. i use repti calcium sand. i thought/think that im doing everything right. this is my first bearded dragon, hes eating fine, and is very alert and happy. but i just dont know if his feces is suppose to be that way.

-please help

Answer
This depends on what he is eating, lettuce is the common diet to the bearded dragon. If you are feeding him iceberg lettuce you need to change his diet to romaine lettuce ONLY. everything you have been describing seems like you have the perfect home for your first bearded dragon. But i MUST know the diet you are feeding him/her, Please give me more of a description.