my gerbils smell!

Question
hello shawntiah,
my name is Peter and me and my girlfriend Jess own a breeding pair of gerbils and they had their first litter in may, their currently raring their second litter. in the last 3 weeks we've had to clean the tanks alot! as their starting to smell really bad!!when we clean the tanks in a matter of a day or two it smells like "vineger".... we realised it started when we took out the sand box which they use as a litter box, do you this would have anything to do with the issue? have you any other suggestions which in your mind could cause the smell and wat could we do to prevent it! thank you for your time, we look forward to hearing from you.  

Answer
Hello Peter,
the best thing to help keep smell at a minimum is Bi-odor for small animals. You put it in their drinking water and it cuts down on the urine odor. The litter box may have helped deal with the smell. I would put the litter box back in the tank and if the smell doesn't go down, I would see about taking them to a vet to make sure that they don't have any urinary tract infections, or I'd at least call a vet and ask.