I'm being cautious - but being cautious is the way to go. Patience is very importent in this hobby, they say nothing good ever happens fast only bad things do, take your time and do it right and learn from others setups. You could get away with less time then a month if the rock you buy is a a very high quality and then you test your water for the cycling process. You will need amnonia and a nitrite test kit. Test for each about 2x per week untill both go to zero (can take as little as 2 weeks sometimes but definitly more then 1 week!) then you can slowly add one thing at a time. But as I said waiting a month is a ggod thing cause it lets your tank more then just cycle - it allows time for microcrustaceans and other organisms to reproduce.