I am thinking about getting a BP this year and I am in the process of making a shopping list of everything I will need to buy. I am going to buy a heating pad along with a ceramic heat emitter for heat. About how many watts should the UTH and heat emitter be?

Also, is a 20 gallon tank ok for a BP? I will be starting out with a baby BP and some people say that it will be stressed in a large tank. Is that true? Also, will the 20 gallon long be ok for when my BP gets older? The tank I have my eye on is 36 x 18 x 16.