A skimmer is always recommended in a SW tank. It will pull out all extra nutrients and will help control algae problems as well. I would suggest the AquaC Remora.
I would also add the remora skimmer. You may also want to think aboiut removing the UG filter as it will give you problems in the long run as the nutrients build up from the detritus trapped underneath.
For a tank that size, a CPR Bak-Pak is going to do a fine job of skimming as well. If a remora is out of your price range, you can get bak-pak's for $104 + shipping online.
__________________
Former advisor and planted tank geek...life's moved on though.