I am not tryin to be mean or difficult in any way, but it is hard to give you and answer when you do not know specifics. From what i know now if i were you i would go out and purchase a decent skimmer. Then i would get a 20l aquarium and custom make a sump. I would get about 50lbs or base rock from reeferrocks.com and seed it with like two pieces of the rock you have now in the 75g tank you have. After cycling is complete transfer over the rest of the rock and inhabitants and you should be good. Unless you want to go bigger than a 75g, maybe get a 90 or 120. Then you will need a bigger sump, skimmer, more rock, everything. I wouldnt reccomend taking out the biowheels now becuase you might caus another cycle and kill off you inhabitants. But on your new tank i would not run them and use the filter to run carbon.
HTH, Mike
*edit- biowheels have been known to raise nitrates in your tank. are you currently testing you water, if so what are your parameters?