It will probably have to be 36x18 unless i get rid of my africans and make room for a 4ft. one. I alredy have a 55 so forty is the biggest my dad will let me get.
Actually a 40 Breeder provides as much surface area as a 55....36x18= 648 48x13=624, so you should be fine. Surface area is the key......Keep the Africans...