I used this sand on my 60 cube and 93 cube right now. I didn't rinse it either, just cut open the bag and dumped it in. It was KINDA cloudy for about half an hour and my water went clear after that. I used it when I transfered everything from the 60 to my 93. I used everything over except for the sand. I used 60lb of new sand for the 93 and I didn't rinse that either. I had no ill affects from it and everything looks healthy right and it's been about a month after the transfer.