hi i was wondering what type of substrate to use for my 2 rf's and what to use for their nesting box. one tortoise is like the size of a softball and one a baseball. oh also at what age and/or size are they when they can start mating? does the female only lay eggs when they are fertile? um how does that work? i have them in a 40g breeder tank and i want to decorate it to look pretty and to make it more like there natural habitat. any ideas? thanks and sorry for all the questions!