I like the dimensions of your tank. If it's not too late, have the back of the tank notched for an external overflow and do a BeanAnimal. (that also is assuming you have enough room behind the tank.) That way you don't give up any internal space and still get all the benefits.
The BA delivers exactly what your looking for - dead silence with absolute safety.
The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man. - George Bernard Shaw