Amy it is one of those dial hydrometers, it was only a cheap one so im begining to think its just really useless. The tank is ventilated by mesh at the top and little vent slats along the front. A little after you replied last night the humidity was reading 75% this morning then I turned the light on its literally shot up to 90% and by just putting my hand in there I can tell it is not that humid at all.
Any one reccomend a better type of hydrometer?