Beginner in need of some advice

[Faithinc]

So I've been trolling around the saltwater-reefkeeping-wallet-burning hobby for almost a year now. After doing arguably more research than my last year of university, I've made the leap--I bought a tank! I'll throw my start-up basics out there and what in intend to purchase in the coming months before starting, but the big question I have involves water, drainage and the essential set-up of the system. (I've only got the tank/stand/sump/lights at the moment)


-55g Tall aquarium 36x18x22" (-2" height due to bulkheads)
-30g 3 stage Sump 24x12x24 (Skimmer>Refuge>/Carbon baffle/>return)
-Vertex 120 (or) BM Nac7 Skimmer (leaning towards Nac 6/7 due to footprint size in a small sump)
-Vertex Illumix 36" LEDs (single strip w/ option to expand later-blue/white combo)
-2x Powerheads (700gph/550gphs)
-Planning on 5lbs Fiji LR w/ 1" Sand bed for a base.
-Cleaning crew
-Planning 4 fish and mostly LPS, mushrooms, and 1 anemone (eventually if I can keep everything alive)


1) Does a dual drilled tank (2 drains) with drilled return need a pump to extract (suck) water from the tank, or will gravity do the work for me? Bulkheads are 1" (600gph) with 3 90's to enter the sump. I've throwing around an idea to install a screw-90 into the bulkhead facing down and 1 facing up. That way if the one downward facing drain can't compensate and begins to over-flow due to excess water being pumped in, the 90' facing up should cover the system to stop flooding... or am I crazy?

2) What size of return pump would I need? Is there a risk of flooding (via pumping too much water back in) or a risk of not being able to drain enough?

3) The inevitable light question! Will 1 strip of Vertex LED's cover my initial tank

4) and finally... what's the best way to jump into getting the system set up. Live rock + sand then dump in water? or water then sand+rock?

Thanks for reading !!