I'm planning on doing the same. I feed worms mostly, blood or live black worms. I recently got him on shrimp and I'm working on massivore pellets. He's in with two Datnoids, one Flagtail and one Arowana.
Everyone says Rays are overly sensitive to Nitrates, I haven't seen evidence of this yet, but I change 50% of the water somewhere around once a month and have a large canister filter...served me well so far. I've had the Ray somewhere around 6-9 months. We'll see how he does long term.
Yep I made the mistake of putting some crush corals in with my sand but I do have majority of the corals in my filtration flow. I might siphon all all the sand and go bare or my dried white sand without any mix corals.I usually feed all of my fish once a day. He rarely hides in sand, I use the Lapis Lustre Monterey Sand. I put coral rocks in the overflows so the water washes over them. It's said it's best to give Rays small grain sand with no coral, so it's easier on their skin since they're always in contact with it.
Mine are 5-6" diameter. My female motor looks a big bigger and my male is a marble motoro. I heard marble motoro don't get as big. I'm worried the female will outgrow and become too big for my male. Is your male a marble motoro too?I dunno, maybe 8 or 9" across. Hard to tell through the glass. He's definitely growing and coloring up. I had a glass bottom for a while but it gets dirty so fast.