I have had my tank set up for about a week now. From what I understand you want to let it sit for about a month before adding your first fish? I did add Bio=-sphere, which says makes water ready for fish right away, but figure I'm better safe than sorry. I was reading a post on R2R and it recommended waiting like 6 months until the tank cycled and was completely full of algae, but I would rather not wait that long and have my tank get that ugly! I do have a carbon reactor and UV sterilizer, to avoid algae. I have a 125 gallon tank with 160 lbs of live rock and about 1 1/2 inches of live sand, RODI water, big skimmer for 200 gallon +