Johnny, your sandbed is fine: rather than vacuum, which disturbs your sandbed, get a few nassarius snails: they go under the sand and do it for you.
I checked your pix: I'm not seeing any redbug. Those are incredibly tiny, and your magnification isn't enough, but it's almost good enough I should see something if they're there. I do see something red, but that's not it. You'll find life moving in on dead coral pretty fast, so that's probably it.
I recommend you go to the coral expert fora and do some looking at pix: find out what redbug looks like---for gosh sakes dip your corals or have your store do it! ---and that wounded bubble can recover, if you'll just move it apart from the hammer coral. Get about 8 inches of clear space around each coral, downcurrent, and you'll have far less trouble.