New Years Day Macro (1/1/2021)

trying to remember the math, but surge will extend to a depth equal to 1/2 or twice the wave interval.    It's a bit unusual from my recollections to have surge at most Catalina boat sites, but if you were at Casino Pt, less surprising.    2-4 ft, otoh, it not so bad.    When it's 10 or 20 ft, photography becomes nearly impossible, though it's fun to play underwater Tarzan from kelp line to line.

Generically speaking, particulate matter gets worse as the day goes on (and wind builds), and also as the sun rises towards the vertical.   In the early hours, the matter is there but not illuminated.

As for the camera settings-  yes, definitely want to kill auto iso, esp on any camera that doesn't allow you to limit the range.

For macro on a 4/3rds, good starting position is base ISO (which may not be the lowest setting - like 200 on your's), F/8 or F/11, and your max flash sync speed (1/200, 1/250, or 1/320).   Strobe set to manual power at 50%.   For here, you adjust strobe power as needed, and occasionally the F value.    This gets you the black background and full subject isolation.   Angle the strobes so the edges illuminate the target and so that the water between you and the subject are missed.

You want the strobes to do all the lifting so the sensor can run at minimum noise.    This does mean a lot of manipulation of the strobe arms, so better to use two segments on the arms, rather than one long one.   In some cases, with small close subjects, the strobes are aimed backwards at you as a result.