I'd say 1st off what type of tank do you really want - corals or just fish. Fish can handle things like nitrate and P04 where as alot of corals cannot. Large predatory fish salt or fresh produce large amounts of solid wastes. Skimmers will help remove dissolved protiens not solids - gravel vacs do solids. W/C's are very much ness. they replenish - hydrogen, salt, calcium, mag, 02, and trace elements the tank cannot produce enuff off all by it's self. Fish don't need the UV high band to survive most corals, clams, and anemones produce their own food - photofeeding - so for corals T5 HO 10,000K minimum. Stoney corals don't like alot of dissolved protiens so skimmers are ness. for alot of corals. Salt doesn't evaporate, fish can handle flux. in salinity better than corals and inverts so daily top off for corals. 50% weekly water changes would be like $200 a month for you in salt alone - try 10% weekly and let your testkit tell you what you need and don't need. It took my 210 gal salty 7 weeks to cycle with LR, the LR should be 1/3 the total volume of the tank - this is your main filtration for your system. Your also gonna want powerheads - probably 4 - staggered on the side wall in the tank slightly facing each other - this helps eliminate dead spots/gas traps, circulates 02, and holds food for corals in suspension.