HOB Fiulter or no filter...

I would gut the filter and just throw a bag of activated carbon and a bag of phosphate remover in it.

 

To expand on Travis's advice which I agree with: Reef Tanks use almost all natural filtration. Most people will use a filter sock on the return but change it at least weekly. The problem with any mechanical filtration is detrius gets trapped and turns into a nitrate factory. We have enough problems with nitrate in our tanks without adding that. Once your tank is well established it will stay amazingly clear. So just use that filter for chemical media like Travis mentioned or for short durations to polish a new tank or when something has been stirred up. Hope this helps.