I have 2 cats, a 1 year old and a 9 year old. I scoop the litter box every other day, and vacuum and clean my bedroom often. However, it still smells like ammonia, all the time. The smell makes me sick. I've tried scooping the litter box on a daily basis. And the smell won't leave. I've checked every where to see if one of them urinated out of the box, and they haven't. Any suggestions to get rid of the smell? Without using a simple spray, that only masks it for a short period.