Pet stores usually see nothing wrong with a snake shedding in flakes, unfortunately

A digital hygrometer or temp/hyygrometer combo is your best bet. Big stores liek Wal Mart and target should have seomthing to foot the bill in or near the hardware section. WalMart used to carry the Accurite brand which is more than functional if you have a single BP.

If by "tank" you mean glass there are a number of routes - the open screen lid is the main culprit. Also what is your source of heating? Heat lights suck moisture right out of the air as well. Here is some great info regarding humidity/glass:

http://www.ball-pythons.net/forums/s...searchid=38620

and you'll definitely want to peruse this:

http://www.ball-pythons.net/modules....warticle&id=52



(EDIT: click SEARCH (on the title bar above) > Advanced Search > select Search > under keywords enter "humidity" then below that select "search titles only")