OK, here is Monty's recipe for cycling tanks.
Tank Cycle Instructions

Set up tank with substrate and any base rock, or uncured live rock if you are going to cure it at this time. Also hook up your heater as well. At this time, do not put cured live rock in the tank. The object is to completely cycle with no die off on live rock. Add about two or three DEAD cocktail-sized shrimp for every 50 gallons of water. The shrimp can be raw or cooked. Keep good water movement in the tank by using powerheads. Circulation is important. If you are using a canister filter/other filter with bio-media, turn that on after about three days. If you are using a protein skimmer, turn that on after 10 days. This will allow excellent decay and ensure that you effectively peak your ammonia cycle.
After two weeks, the ammonia should peak and nitrites should be starting to rise. In simple
terms, the ammonia converts to nitrite, and then the nitrite to nitrate. Four weeks after you start the cycle, the nitrite should be peaking, and starting to fall. You should now start picking up your nitrate readings. Nitrate is not fatal in the same ppm range like ammonia and nitrite is. However, this applies mainly to fish. Corals, for example, are far more sensitive to nitrate than are fish. However, it is desirable to keep nitrates as low as possible even in a fish-only environment. Water additions and changes generally remove your nitrates, and over time a biological filter can be built up which will break down nitrates as well. Spent gases are released through the surface exchange, which is made much more efficient by using a powerhead to break the surface. After about six weeks, you should have a completed cycle, and now is the time to introduce waste-producing organisms (fish) to maintain that cycle. Also, if you now add your cured live rock, you will not have an ammonia spike killing off beneficial life. Some begin their tank cycle
with non-cured live rock, and in the process effectively “cure” the rock. However, I recommend the shrimp even in that situation as it produces an excellent amount of decay and boosts the
ammonia to start the most effective cycle. One thing you do not want to experience is adding a fish to a tank you “thought” was cycled with live rock only to have another ammonia spike with potential fatal results. This would be the case particularly if the life rock you cycled with did not produce sufficient die-off to peak your initial ammonia-nitrite-nitrate cycle.
On a side note, this will be when your tank smells it worse, and potentially looks its worse. You still might experience your brown diatom outbreaks and possibly at least one red-slime algae outbreak. This is all natural and no sign of poor husbandry. Your tank must “get worse” to “get
better”. This is why allowing sufficient time to cycle is so critical.

AS A DISCLAIMER: There are MANY ways to cycle a tank, this is just a tried and proven way to get the results of a complete cycle. There are variations on the methods described above. Some people DO cycle with live rock. There is no one “right” way to cycle, but several proven methods. This is one such method that will get your start in the hobby off in the right direction. You will learn the patience of not adding fish prematurely, and hopefully take the 6 weeks cycle time to do some informative research and general reading in the hobby. You will find that after your tank is cycled and you have spent that time reading, you will attain a secure level of comfort that you “have an idea what this is all about.” This is the most important time you invest in the hobby, for it will dictate whether you nurture your passion for marine aquaria, or become frustrated with “too many problems.” Again, this is not the “only” way to cycle a tank, just one of the most thorough. Too many people lose expensive livestock by rushing their start in the hobby.
Patience is a virtue, and if you can’t “hang on” for six weeks, it is a good indication of which way you will go in the hobby. As you gain experience, you will find that you can “instantly”
set up a fully cycled tank by using water/substrate/liverock/bio-filtration from an established tank. Don’t confuse this method with a brand new tank, brand new water, brand new
rock, etc.

Good luck, have patience, research every fish/coral/invert you purchase and you will find the rewards of this hobby are nonstop. From personal satisfaction to friends/family marveling at your tank, you will feel a personal sense of success and satisfaction that comes only when you “do it
right.”
Unfortunately, you will lose fish. It is your responsibility to make sure you don’t act in such a way as to promote stressed/diseased/dead fish. That is the difference between a marine
hobbyist and a person with a saltwater tank. Always ask questions, always get many opinions, and have enough of a foundation to sort through and make your own rational decisions. And remember, when you think you know just about everything, its time to crack some new books
because aspects are changing constantly and nobody I know has EVER mastered this hobby. I hope this helps out some newcomers to the hobby with questions about cycling. This method is in my opinion the way to go over using live fish and subjecting them to the burning of ammonia and potential death therein. Keep a log of your ammonia-nitrite-nitrate levels as you progress and you will see the closed-system eco-cycle unfold before your eyes. You will also accurately
determine when the correct time is to add fish. Six weeks is the general approximation, but can vary depending on every tank setup, and filtration methods used. Happy fishing all, and welcome to the most stressful, peaceful, agonizing and fulfilling hobbies I know of!!

Fish Whisperer