You are on the right track. I would say its more 6 to 8 weeks. Idk but 4 weeks may be to short. What you are trying to accomplish is starting the nitrogen cycle. Which after the cycle has complete and you parameters are in good condition. When this happens your tank should have good bacteria. Why is it important? Well, ammonia which is fish waste. This can be very toxic to pretty much anything. This ammonia turns into nitrite and the good bacteria pretty much consumes it, in return you get nitrate. Then doing water changes you get rid of nitrates. All you will need to start the cycle is something to cause an ammonia spike. Many people use a raw shrimp. You can use fish but this is extermly hard on the fish itself. I think you can do it with live rock, in which the cycle time could be shorter but I would still recommend the 6 to 8 weeks. Just to make sure your cycle has completed. While doing your tests over the 6 to 8 weeks you will be wanting to see a spike in ammonia then nitrite then nitrate. But you have to make sure that your nitrite goes low and stays low before adding. After this has happen you should do a 15 to 20 percent water change. I think then you will be ready for certain types of fish inverts and corals.
