I have done both ways. I find it easiest for larger tanks to fill with rodi and add salt. Just add your sand after. This creates a mess though. I also dont want to rinse my sand with my well water and using rodi would be exhausting. Most say the caribsea live sand isnt really live and you should rinse it. I did my current reef by placing dry rock, filling with rodi, add salt, let it run for a day, check sg and adjust if needed, shut off flow add sand, Use some sort of mechanical filter material to clear water for a couple days then start cycle, its about 120g. New tank is 180g with a 100g sump and I will most likely do it the same way.
