Join Scubaboard.com and check there. There is always loads of info. We did a night manta dive on the big island, which was the only reason we even went to Hawaii to dive. I did the research and most diving boards I read said the best diving was on the big island, we had been to Palau and hoped to see the mantas there but were just sol. The day diving was just o.k., I've seen better in the caribbean. The night dive was cool for about 5 minutes then it was just hectic and boring. My DH does video so we did have a little manta get attracted to his lights and followed us all the way back to our boat, which was kind of cool.