I see your point about the interesting nature of the polyps in the base and thus why you chose to set your focal plane there.
There is an unfortunate reality where objects in the foreground which are out of focus can be very distracting, and that is at work here.
Might I suggest both using a tripod (and remote shutter release or self timer) and turning your pumps off. Turning your pumps off will reduce / eliminate polyp motion and using a tripod with either remote shutter release or self timer will allow long exposures that will work with smaller aperatures / greater DOF. Plus it is very difficult to handhold a 105mm lens for 1/50th of a second without some motion blur, just from being human and not a fixed surface. Some people can do it. I cannot.