[fatman]

You might even consider using a little vinegar in the water to clean your old sand before using it in the new tank. It will actually etc the syrface and therefore remove any calcium carbonate hat attached to it along with phospahtes as part of the clcium crabonate precipitation process. I would consider using about a quart of the sand from you old tank, and then diluted vinegar wash and rinse well to reuse. Unless you can get aragonite sand cheaply, if so just throw it a way. Sixty pounds of live sandis to little to be really effective by itself. It would make a good topping however for a thicker layer of fine sugar sized sand.