Welcome to 3reef Paco, the first Q is free .25 after(j/k) Whom ever is giving you advice on how start a SW tank(probably LFS) isnt steering you in the right direction. The cycling period CAN last up to 12 weeks. Since your at 2nd week, you shouldn't have ANY livestock in that tank. You can add one fish after the first month has past by. You can add more fish AFTER you have finished with your cycle. Add the fish ONE every 3-4 weeks, remember that fish product the most waste(bio load) and the Bacteria needs to "catch up" with the new load. Read this site, it will explain alot about SW systems and how they work, it even comes with a glossary so you can start "talking" the lang. Saltwater Aquarium Setup Guide Hope this sheds some light and helps you with your journey. Luna _________ 9YR OLD 90G 30G w/d Mag18 150G skimmer 692w MH,yel&kole tang,foxface,midas&convict blenny,B&G chromies,Blk/yel fin chromie blackcap,nemo,neon goby,6line; Blastomussa Merleti,Acan ,BUBBLE,Torch,LTA, Goniopora(2), Acropora(2),Brain, Moon, assort zoas, yel& G star polyps, R&G open brain, P&B ricordia, montiporas, cup&candy corals, enias,B/G mush,flower ane(2), cherry red mussa, dusters,cleaning crew  |