My first was in a 20L because I did my research. Then a few years after that I switched everything over to using rack systems I built and you couldn't pay me to go back. Those mesh screen covers that tank can use never let the humidity stay right. Someone even told me to put aluminium foil over the screen to hold it in and I thought heck no, I bought the tanks to be able to see them. There just came a point when you have to say the python might not want to be seen and might feel more secure in a smaller enclosure. Btw, while in the 20L my new female baby ball would only eat a small mouse about couple of weeks, after switching to rack she started eatting the one same small mouse every two days.