I disagree, I worked in the Keys and did night dives at least weekly and used my 10w HID on everyone of them. I usually had a gaggle of divers following me around cause I was throwing so much more light then their PT 400s. That being said, the coolest part of the dive was when I turned my light off and hung in the darkness for the last 10-15 minutes.A bright HID light is great in murky water. But way overkill in the caribean!!!