To get the most out of your camera you need to use Manual Mode, not Auto, when it comes to underwater photos.
YOU have to take the photo, not the camera.
The internal strobe is good for Macro shots under 3 feet and even better at 2 feet.
As for the non-strobe shots, Manual White balance will yield the best results, not blue results. That means you have to calibrate your White Balance off a clean white dive slate at the depth you are taking the photos. When you edit them in Photoshop or the like you will see great results without using the "mandrake process" which puts red back in the photo.
It all boils down to knowing your camera inside and out and being able to change the settings quickly and efficiently to suit the needs of the target.
The use of a filter is, and remains controversial. I did a quick comparison on a recent dive and saw very little difference in using a filter. The test was not scientific but the results are
here.
There are those that argue whatever results a filter can yield underwater so can a software program after the fact. I can't answer that one but I personally see no need to carry a filter when the end results for me are as shown on my example.