New to marine tanks, need some help...

[marvinsae]

so i use to collect fresh water fish but i stopped about five years ago. i've decided i want to start a marine tank and have been doing some research for about a week and this is what i have so far.

i plan on starting up a 65 gallon reef tank (i was advised a marine tank should be at least 18 inches thick) with a 40 gallon sump. in this sump i will have live rock, a protein skimmer, heater and a pump and all that. so i've been told i need about 20-40 gph per 1 gallon i have in my tank. so that would work out to be about 1300-2600 gph flow and i can add power heads to help boost this? would the sump, live rock in the tank, and live sand be sufficient enough for filtration? as i stated earlier i will also have a protein skimmer in the sump. all of thise equipment i will be buying second hand for about 250...but i dont think that includes lighting

also, with lightin i will need around 5 watts per gallon but more if i want to grow other corals such as clams. so i'm thinkin maybe 6x54w t-5 lights or 8x54w lights. metal halides are a bit too costly for me at the moment. my question is would 8x54 lights be too much or would 6x54 be sufficient to grow any coral i want?

now i know that when introducing new fish i shouldn't put too much in at once or else the ammonia level could be dangerous. but, what about reef janitors? do they effect the levels? what's a good set up for reef janitors? i'm intersted in starfish, blood shrimp, possibly some hermit crabs also. which are the safest that won't harm my coral?

is there anything else that i may be missing? i haven't been able to read up on much additives yet either. would someone be able to shed some light on that?