|Yeah, well, I have a 7 tons of TiO2 on the floor, as we speak. Will that do it? hehe The chalenge would be working up a binding agent that is both fast drying and not something nasty for the sea. I'm thinking something like a Gum acacia. It would eventually disolve but it would last long enough. Of course developing coatings is never that fast and simple, but it could be done. I would also play with mica platelets or a synthetic mica (potasium magnesium3 aluminum silicate?) coated in a TiO2 for better refraction.
If I had more time I'd work on it. But really, it sounds like a gimick to me.