If you have the time....and you really want to change it.....then go for it. Should definitly clean up the water.....specially long run. I recently did mine and it's not bad. I had my rock on top of 3" of aragonite and CC and decide I just wanted a very
shallow sand bed, needed to get a few fish out, and redo the coral layout for the soon coming SPS.
This is not to bad of a project.
Get yourself a few powerheads, and some rubbermaid bins, and heaters. Start siphoning/pumping water into the bins. As water level drops put the soon to be exposed rock into the bins. Net fish when all rock is out.
It took me about three hours to get all out of my tank. Then about 5-6 hours to redo the rock and add the water.
Here is a thread of my project.
http://www.thereeftank.com/forums/sh...ad.php?t=62514
HTH!