new to marine

okay, I will start out by saying I am experienced in freshwater but marine is a whole new ball park!
My fifty gallon is completely empty, and my planned setup is 3 15lb bags of carib sea argonite, and i bag of crushed coral, 50-75 lbs live rock, an aquac remora pro protein skimmer, and really expensive lighting *sigh*(I am shooting for reef tank).
My confusion lies in 2 things, first I dont know what kind of current devices to use or how many and I am confused about refugiums. my tank is not pre-drilled and if I get a tidepool S.O.S. skimmer(overflow) could I fig it up (simply) to the ten gallon tank I have as a refugium? I want to do it as simple yet effective as posible. I have the concept of a refugium down but dont understand the setup.
one last thing is are there any problems with not having media filtering?