I'd change it out as gunk collects in it.
Yes..you should still be reading! lol Do you have all of your test kits ready to go?
wats your calcium level. are you gonna be putting in SPS? I would start off with beginner frags suck as mushrooms, yellow star polys, or green star polyps.
BTW, what's your salinity level? Are you using a refractometer?
You really should be testing your Ca, Alk, Mg and PO4. It's much easier to get your tank in balance when you don't have to worry about livestock.
Russ