I moved to a new house about 6 months ago, and initially, I was going to keep the sand. After seeing how much detritus had build up, I decided to toss it. I don't know how big your tank is, but spending 60 bucks on new sand seemed a much better idea than having a mini cycle or having to spend a few hours trying to rinse and clean the sand. If you have liverock, the sand will become "live" again.