Hey there - shouldn't take weeks, but likely more than a couple days. The more time you give it, likely the better colony you will transfer over. Just make sure there is some nutrient source in the new tank when you do transfer it over (phantom feeding, one fish, etc.) or the population may be impacted. Still go slow when stocking the new tank, as the media is just a seed, and you'll still need to give your new tank time to build the appropriate size bio filter as you add livestock..