I just moved all my old sand to my new tank, BUT I only had about 40 lbs to move at best AND it had only been in the old tank for only 4 mths. I also have 2 Sand Sifting Starfish and an Orange spot Goby constantly sifting through it so when I siphoned the sand into the bucket, I used some of the tank water to swish through it and kind of rinse it and then added it to the new tank. The new tank was cloudy for a bit, but it wasn't as dirty as it could have been had my old tank been running longer i'm sure.
If I have to move again, i'll probably only take a small bucket of the old sand and then just seed the new stuff. I agree it's not worth the headaches of running any spikes. Sand is "cheap" enough, compared to some of our fish and corals
