any saltwater aquarium ppl here?

cause i have a ?

i just wanted to get some input on a protein skimmer. i am currently setting up a 75 gal. reef aquarium with a 7 gal. sump and fluval 405 filter. i am looking for a skimmer to run but am running into a snag. would a 65 gal. skimmer be good enough for my setup or should i go with the 125 skimmer? just by looking at the numbers it seems like a easy answer but a 75 gal. actually only holds around 65-68 gal. after displacement and inner dimensions. any input would be greatly appreciated.

I have a red sea prizm pro 300 gallon skimmer for sale. $100 its yours in original box. Always go overkill on the skimmer!

this is the link…deal of a lifetime

http://cgi.ebay.com/Prizm-Pro-Deluxe-Skimmer-up-to-300-gallons_W0QQitemZ140163213652QQihZ004QQcategoryZ20759QQssPageNameZWD1VQQrdZ1QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247