PatW
Contributor
In my first dives, I often came up with what looked like lots of blood. I had difficulty equalizing in those dives. The effort and force of equalizing probably caused a few capillaries to rupture. Also, my nose produced a fair amount of mucus which I would blow out when I surfaced. A little blood in some mucus can make a really impressive mess. But I know from my days of working with blood as a research tech years ago that even trivial quantities of blood, like 1 or 2 mm, can really LOOK very impressive. Blood has so much red pigment, hemoglobin, in it that tiny quantities can turn large volumes of liquids a bright red. Now, as I became reasonably proficient at equalizing, I stopped seeing blood. I sometimes still get the mucus production.