Well using your 'old water' will do nothing. Read up more on simple water chemistry until you know those type of questions and THEN get rays.
Your old filters will help seed but your old water will not.
You are on the right path by re-searching and asking quesitons. Spend a few more weeks learning as much as you can. Rays are not begginer fish by any means, but some one with just a little experience but alot of research and willingness and abillity to learn could also be successful.