Is the ten gallon tank for one of the two listed in your signature? If so, then you may want to consider a larger tank soon! As for cleaning it, you should spot clean it every day. I typically deep clean my enclosures every week or two. Sometimes it depends on feeding, though. If one of my snakes doesn't feed for a couple of weeks, then I might be able to go a little longer...no eating = no defacating! The water should be changed (and the bowl cleaned) at least every other day, in my opinion.