Proper lighting is probably the biggest secret to underwater photography. Its all about angle of your strobe and output and trying to eliminate as much of the water column as you can (getting as close as you can). Here are some really basic hints.
Before you even start with your camera make sure that your buoyancy is up to scratch. Something disturbs the viz and if its you - then by taking that out of the equation you are already on your way. If you come across a great subject (like those ghost pipefish you pictured) then take a little time to get your strobes set up away from the subject, then move in really slowly and avoid excessive movement kicking up the particulate.
keep the distance between the subject and camera to a minimum - get close!!!!
angle your strobe away from the subject so that the subject is lit with the ends of the strobe beam. you can work out how wide your strobe beam is by simply bracketing your strobe angle.
use low strobe outputs the first thing people tend to do is blast the hell out of each image. The key here is SUBTLE lighting. start at the lowest setting (1/8th) and go up maybe one or two increments MAXIMUM.
The only way you can see particles in the water (backscatter) is because your strobe light is reflecting on them thus your camera will pick it up.
And thats it!!! None of this is difficult, it just takes time to perfect. The more pictures you take - the more likely you are of finding the "sweet spot" angle of your strobes, then you will know this angle in the future and all your pictures will be backscatter free!! So get out there and spend a few dives working on getting that strobe angle right, remember LOW outputs and get close!!
Here's a couple pictures with what I am getting a lot in terms of backscatter. My single strobe is positioned up and screen left. More lately I'm trying to position the strobe directly above and pointed at the lens. Am I doing something wrong?
Since there's was a good amount of particulate matter in the water, is there any way to light this so I wouldn't get backscatter?
Do people usually get some backscatter and just remove it later in post?