It's a completely alien world down there.
Although I sometimes wonder who the aliens are, we're entering into their world after we spit polish our masks.
They don't live by our rules, they don't communicate like we do, and they don't see what we see.
They got some pretty freaking awesome secrets, which you'll get a glimpse of under these wavelengths;
Actinic Blue Wavelength
Fluoresce and reveal colours not visible under normal light in some corals. For best results use a yellow filter over your camera lens to filter out excessive blue.
True Red Wavelength
Most creatures underwater cant see red. With a true red light, the creatures won't even know you're shining a light on them, giving you a chance to closely inspect their behavior or get your camera ready for a shot without spooking them off.
If using the red light to help your camera focus underwater, your main strobes will overpower the red light once fired, so you can leave it running continuously.