The lfs told me that carbon was not good for reefs... but after reading
books, magazines, and online sources(which I should have done first) I find
that I should have gone with a refugium and sump, instead of dumping money
on the canister filter.
Lesson learned: LFS operate to make money, and only occasionally have your
best intrests in mind.

But since I already have it, I might as well still use it till I can set up
a refugium.