yeah, it's hard for me to tell from your pics, but whatever it is, it's not too bad yet. I would do a lights out for a couple of days and put a one hour nap in the middle of your regular light period. Do some water tests and see how much nutrients you have. One of the thing that seems to feed dinos is silica, and this is replenished by doing water changes.
One way to test and see if it's dinos it to thoroughly blow off the rocks and walls. If it is back on them the next day, you can be fairly certain it is dinos. They are motile and will settle right back all over everything.