a cheap PAR meter is around 350 bucks. don't count on this one being accurate.
you want to find a R.O.D.I. unit, not just R.O. many of the ones on ebay have the flavor cartridge at the end, which is basically just an extra carbon cartridge and unnecessary.
you want a 5 micron sediment, carbon block and the membrane, plus the D.I. resin chamber.
as for the frag tank, 30" is not an easy size to cover. i would probably get a 6 bulb t5 fixture. i still don't know what corals you intend to keep, but my old 150 gallon was only 17" tall and i used a pair of 8 lamp t5 HO
fixtures over it and sps
did very well.
this skimmer would work for you-
Reef Octopus NWB-150 6" Internal Protein Skimmer
or this one-
Bubble Magus BM-NAC7 Cone Protein Skimmer - English