That and it's just a carbon filter, so it's not going to remove the chlorine, nitrates, or phosphates. R/O water really is the way to go.
Also, I see you've got a Prizm skimmer on a 72gallon tank. You should seriously get a better skimmer before you stock any additional fish. Its a highly inefficient skimmer, and despite RedSea's claims, it is NOT enough for anything over 30gallons unless you've got an insanely low bio load.