After reading thru the posts, I noticed some degree of anxiety about the amount of time it takes for a full cycle to finish, and it also looks like everyone has had somehow different results/experience. Just to give a different perspective: the perspective of patience (and god knows you have to be patient if you start a saltwater tank - too much money at stake!
).
Let's remember that the purpose of fishless cycling is to protect your fish from being stressed and eventually start with a sick tank. It's both healthy for the creatures your taking care of and also for yourself (start off with a neat, healthy tank). It will keep you from going thru a very frustrating experience....
It is by no means a way of cutting down the amount of time you'll wait to introduce your first fish. The key to a successful system is patience (I know! It sounds hard! but you'll not regret it on the long run).
If you're patient enough (and you'll not regret it), you can also do fishless cycling by dumping some fish food in the tank, let it sit and forget about it for at least a week. This can be a way of avoiding the hassle of doing daily water tests (which in my opinion can create more stress and anxiety in the individual). The food decaying process will trigger a cycle process. Once you test your water after a while (maybe two weeks) and ammonia starts to decrease and nitrites start to increase, you may syphon the remaining detritus, if you will. How much food? Just enough (it only takes a spark to start a fire...). It may not be a one week cycle record, but the purpose is the same. In the meantime, you can read about the fish you want to keep, the substrate you plan to lay. Plants you want to buy. Lighting requirements, fertilization. Husbandry, etc.
You may find that 5-6 weeks were extremely useful to feel confident that you're system has a low chance of failure, now that you're more educated.
Just a thought I wanted to share folks!
That's sort of my plan if I decide to start a FW tank.
*celebrate