a 55 gallon would be more suitable, but the 30 gallon would work until you could afford a larger tank. i think 40 gallons are perfect for adult bp's if you like housing in tanks. i wouldnt use a 10 gallon for even a hatchling bp man, they blow. hard to keep the temps and humidity accurate, not to mention are easily escaped from. most 10 gallon tanks these days are made really cheap. use the 30, it'll work fine. as long as you supply an ample amount of hiding areas for your bp the size of the tank shouldn't matter as far as being too big is concerned.