In my oppinion, tanks are great for the cp's that require humidity. However, I have found that VFT's, Sars, some 'dews and a select few neps fare much better outside of a tank...even in humidity as low as 40%. All of my sars and vft's (as well as most of my dews....and this year a nep or two) go outside on the deck in the summer. My big tanks are reserved for plants like the bical (lowland) and aristolochioides (highland) that really need air you can swim in.