Ok so I have 50lbs of Live rock with some coral, I had it proped up nicly till I spotted this lil black crab thats been hiding, needless to say the tank is in disaray in my venture to catch this SOB

. So my question is how can I semi/perm glue my rock together so I dont have landslides, do I use silicon if so what kind and whats the best way to setup the rock (pattern?)