Sand question (Can I use this?)

[DracoKat]

I have fine black sand I used for a FW tank long ago. been long since cleaned and dry. I am wondering if its OK to use for a reef tank?

 

[KC's CNC Creations]

you can.......but most black sands have iron deposits within them and they are attracted to magnets, they collect on pump impellers and ruin them as well as attract to the cleaning magnet and scratch the hell out of the tank.

 

[N.Sreefer]

I would only use calcium carbonate based sand in a reef. The black sand may be silica sand and the cost of sand is nothing when you add up how much the reef costs. Rather than losing livestock down the road and having to tear the tank apart I would be safe instead of sorry later.