Problem is, there's no "set time" where a tank cycles. That's where the liquid test kit comes in handy. You sit and wait (a beautiful chance to develop patience) until that day comes where you have 0 ammonia and nitrites and a low level of nitrates (if you're not having fish at all in the tank during cycling throw a couple flakes of food in every couple days to decay and produce ammonia). Hope this helps a bit....