Rays are a centerpeice to me... so putting them in with other centerpeices really doesn't make sense. Especially when they CAN kill the ray. Your going to have people say it will work and it may for them but I would suggest doing something a little less likely to kill your ray.
Good filtration is a key start. I'd suggest yepesi, or motoro for a begginer however motoro's will get too big for your tank. Yepesi it's unkown as of yet (to my best knowledge)