There are cases for cell phones, but I don't have one. Or a camera yet either. Someday after diving skills improve a bit more.
I don't know how big a manta gets, but I was diving in Costa Rica last spring and four or five of them came sailing right through the group I was diving with. Visibility was outstanding, but even so, they seemed to glide out of the gloom and then disappear back into the gloom. They seemed enormous, and the whole effect was completely thrilling. They seemed like the could have easily been 20 feet tip to tip. One of the people I was diving with had a camera and took video of the rays and a curious octopus that played games with us.
I don't think this will ever get old. There's something different in different places. Diving in Puget Sound has a zen quality to it that's really different from tropical water. Since the boy and the girl live in Monterey now, I am hoping to dive there and see what the kelp forests are all about. Recreational divers like me only scratch the surface of what goes on under the water. It's a little like walking around on beaches and thinking that is what there is to know about life on land.
There are reminders of how unforgiving it can be. There was a dead harbor seal on the bottom last Saturday morning, with crabs busy feasting on the carcass.