Replace live sand or use original?

Agreed. I was under the assumption that he knew the tank's "history".

 

i got a 100 lb bag from Home depo for my sand when I moved tanks it was like 7 bucks for the bag and let my live rock seed it again. but using sand from someone else's tank is a 50/ 50 chance you make bring what ever problems into your tank whether a cup or a all.

 

lots of sand from hardware stores are silica-based, as opposed to aragonite based which is preferred in a reef. i would not recommend going this route

 

If its a good aragonite sand I would simply put it in a tub and add bleach and wash and rinse it will I have washed tons of sand like this never a problem . Id also fill that new tank with water and bleach also fill it to up under the top rim to ensure any bacteria is dead drain and refill with the good R/O D.I water and you are ready to go.. The Bleach word scares many people but it dissipates very quickly once exposed to air and light and at worst it may raise your Ph a little if any was not totally rinsed..