the 120 has been up since sept of last yr I think, but we had a 55 before that, that had been running several months that we added to the 120 if that makes sense. So if you take what was in the 55 its been over a yr if you dont then not quite a yr..lol we really enjoy it.. hoping to add a few more corals soon... maybe some more rock.... would like a few more places to put coral.. other than that.. just waiting for the darn things to GROW