djatl;905725 wrote: It's a tradeoff. Dry rock won't have unwanted hitchhikers, but it takes longer to become live. Live rock could have hitchhikers, depending on the source. Some hitchhikers are pretty cool (sponges), some can be a real nuisance (mantis shrimp), and some pests can be challenging to remove (aiptasia or bryopsis). And live rock that was shipped will have some die-off that you need to handle before adding it to your tank (manual removal and curing).
You've already got a working biological filter in your wet-dry, or your fish would be dead. Using live rock (even if it started as dry) provides a way to process Nitrates, which the wet/dry doesn't. It's not the only way, but things like growing macroalgae in a refugium, running GFO, and your basic water change are all intended to remove nutrients from your system. There are other approaches, but the idea is to keep nutrients lower for some species of coral. Some corals aren't as sensitive to high nutrients (which a well-fed fish-only system is likely to be).
Also, +1 on the RO/DI filter. It helps because you're not putting the nutrients into the tank in the first place.
There's no single answer to running a reef tank. Lots of different approaches work. You should research it, and decide what fits in your budget, time, and interest. I think it's part of the fun!
