Sand vs. Crushed Coral

No worries. I just didn't want to be misunderstood. I've read some surprising "Facts", in the hobby. I don't know about switching your substrate out. Sorry. I would assume that you might get some nutrients released into the water, but your skimmer, and liverock should take care of it, in short order. Maybe, plan the change with a water change, right after? I've, also, read to change out a little at a time. Maybe remove a quarter, and then another quarter a week or two later, and so on. Chances are, if your bio-filtration is well cycled it shouldn't cause a problem. I just vacuumed a bunch from behind my rocks, rinsed it in freshwater, and put it up front, and no issues. I did get a little more cyano. than usual, but that's due to released nutrients, in the water column. Plus, I just got a new skimmer, and skimmer pump for my second skimmer. I, also, removed my diy 'fuge, so, lots has been stirred up, and still, no coral or fish issues. You might vacuum the cc, first. That will help to remove the nutrients productively, instead of into the water column.

 

thanks for our opinion. I think the tank should be alright. It's an established tank so hopefully with a couple small water changes I won't see any major issues.