Transfering tanks.

[doch]

What I did is took my existing live rock and put it into the new tank full of properly salted and all brand new water. I put a few pieces in, let it circulate for about 24 hours, and then added the rest of the rock, all of my coral and all of my fish. I wouldn't keep the water... the water column itself holds no value to you (unless you think that nitrates and phosphates are valuable). The good bacteria is in your live rock. As long as you keep your bio load the same (don't add any new critters) your existing rock will do the trick (you can fill your new tank full all at once). One thing to be careful of is how (or if) you transfer your sand bed... you have to be careful what you stir up and release. Personally, I bought all new sand to avoid any troubles (it was an excuse to go with a different grain size). If you're happy with your sand, take it out, rinse it well, and transfer it over.

For the new rock, just add marco rock. It's cheaper than live rock, and since you've already got good and (I assume) mature, pest free rock, it will seed it nicely. If you add more live rock, you run the risk of parasites (aiptasia, flatworms, bad crabs etc.)

When I switched, I lost one out of 15 fish... a yellow clown goby. Many say that they are not very hardy.