Here's what I would like to do. I have reefer 170 that I want to add sand to. I have a blue haddoni in the tank and have some sand already in that I added when I placed the nem but there is only enough for the nem . The tank is struggling with gha but corals are doing well and encrusting and some have turned into small colonies. I have another system that is thriving and what to me is very mature at 8 years. My thoughts are to place dry sand in containers and place it in the sump of the established tank with no light. What I don't know is how long would I have to leave that sand to make it live and maybe bring some biodiversity from the older tank to the 170 and prevent the uglies that always accompany new sand? Months? Years? Or is it even worth the effort? I'm going to add the sand to the 170 regardless but I'm trying to make the addition of sand a little smoother than when I have done the same previously. Just for info the mature tank is a 180g with 125g as a sump with a total volume around 225g tank is over 8 years old and running pretty much on auto pilot with Kalk and WCs the only thing it needs to keep it going at this point so I'm not too concerned with upsetting that tank by trying to seed some sand in the sump. If you've made it this far thanks. Sorry for being so long winded but sometimes I just have trouble compressing my thoughts.