Advice? moving tank sand???

I think at a minimum, once you have everything out but the sand and water, stir up good to get all the gunk into the water, then you might let it settle for a bit (a lot will stay suspended) and then siphon off the top water and pitch, then siphon out the sand into a bucket (use a 3/4" vinyl hose to get sand + water out) and that goes into a bucket, when the bucket is full of water, pour the stuff off the top and continue until you have 1/2 bucket of sand, then pour off again and start a new bucket. Repeat until done. Then when you put in destination tank, mix it with the new sand.

I don't think you need to rinse it out with a hose like you do new/dry sand, but you could. You would effectively kill anything by doing that, but you'll have clean sand. If you do as I outlined above, you'll get rid of most of the nastiness but it won't completely kill off any bacteria or random life in the sand.

 

Addtion: leave as much water in the tank as you can, it's easier to siphon out sand with the 3/4" hose method if you have a lot of water in the tank. It goes about 1 part sand to 8-10 parts water when you are siphoning it out.