I agree. Its much too small and the open top makes it unworkable. You need a large closed chamber for a RF.
Also, if you don't already have the tortoise, RFs don't do well in CA. It takes a tremendous amount of effort and expense to make and enclosure that is barely adequate for them when they get too big to live indoors anymore. You'd be much better off with a tortoise better suited to the conditions here in CA.