The difference is you had a glass tank... I used a 20gal with my first snake and had problems too but the problem isn't the tank being too big its getting temps/humidity right in glass. Unless you live somewhere where its naturally hot and humid all the time or you have a snake room ,a glass tank is always going to cause problems bc its challenging to get temps/humd right. 99% chance the reason you had problems is bc temps/humid werent right on.