They are somewhat dark on my calibrated monitor, last couple especially.
One can use a colorimeter type device like SpyderPro to calibrate brightness and color on a monitor. One can't be sure the monitor on which one's photos are viewed is properly calibrated, but one can be sure that the monitor on which it was produced is.
I suggest also using a healing brush or similar tool to remove the marine snow from your pics. Bright white flecks can be very distracting. Shooting with pumps off can help to minimize the amount of debris floating around during picture time.