Chinchilla pee/bedding smells?

I recently got two chinchillas, and this is my first time taking care of them. When I bought them, I received FreshNews recycled paper cat litter. It helped absorb the smell however I noticed the chinchillas eating the litter. I changed the litter to CareFresh the paper bedding but then the cage smell seemed much stronger. I'm not sure why, but I'm suspecting that it may be their pee. I'm not sure whether it's normal but I read online that their pee should be odorless but there's a strong odor smell coming from their cage. I just changed their cage yesterday but the odor is already strong. Please help! If I do use different bedding besides fleece, what should I put underneath? And would you think it's because of the bedding or their actual pee? Thank you!