What is the best way to change tanks?

[Edmonton Eskimo]

sounds like a perfect plan to me! You are correct about the sand. I used my old sand once and let's just say I'll never do that again. You can save the old sand though and keep it in a bucket for a while until everything dies and then thoroughly wash it. If you do the switchover quickly then there shouldn't be any problems. Make sure when you siphon the water from your old tank you don't get any crud in it.