So I've just bought and setup my first reef setup this weekend - a new TL-450. I've added 4kg of live argonite, and 6.7kg of live rock, as well as disabling the UV filter and adding some filter floss. I set it up 3 days ago and everything looked great - pH 8.3, normal alkalinity, S.G = 1.025 Over the last 36 hours however, the S.G slowly dropped to about 1.018. I removed some water to add salt and I've raised the S.G to 1.020 - I don't want to increase it to quickly and shock the critters that came attached to the live rock. My question is - is this normal, and am I doing the right thing to solve the problem? I'm using a swing arm hydrometer btw. On the subject of my live rock (pics to follow), I seem to have gotten more than I've bargained for. I've spotted at least 2 tiny crabs and at least 1 shrimp that I can't identify because it won't show more than its eyes. I also seem to have a tiny slug, as well as quite a few little tube like molluscs/animals (not sure what they are, I'll get pics for you guys to help me out). There is also quite a bit of what look like clusters of small green sacules/pollyps. The guy at the lfs told me that this was some type of coral - I'm not so sure.