I removed my sandbed all at once. Many debates on that topic, but I figured that I would encounter some sort of nutrient spike, so I might as well get it done as quickly as possible. I moved all the LR I could to a rubbermaid container filled with cycled tank water. I also used as much of my display's tank water to buckets and other containers as to not waste it. I also made some new saltwater in anticipation of water lost to the project. I moved my sps corals to my fuge which is connected to the sump, which was continually skimming during the process. I then drained the display and started scooping as much sand out as I could, then siphoned the rest out. It was a long day, but long term, I am glad I sacrificed a day off..... In your case, given that you have a smaller tank than I do, the project should be rather swift. Once the tank was free of sand, I then placed the LR and corals back in and put the display back inline with the skimmer. Word of caution, make sure you provide open space, have a powerhouse skimmer, and lots of flow. Providing you meet these standards, you will be happy with the results. BTW, I cannot even tell you how much crap was locked into my sandbed. I guess it was doing it's job, but scary to me in the event of a sandbed crash. Good luck!
