I've never priced 75's with stands, but if the stand is nice, then I'd say it's probably worth it. You could always sell the saltwater equipment off piecemeal and usually reef tanks are well lit, so you might get away with simply replacing the bulbs. Just ask about wattage on the lights. You can grow some decent plants at 2-3 WPG and then at 4 watts per gallon you pretty much can grow anything. If you don't want to do CO2 injection then you want a 2 watts per gallon cieling in my opinion. Still, Never hurts to look, right? 
