Any skimmer is better than none, go for one rated for a larger tank and you will never worry about polluting your tank with protein.
However, part of your problem is not having enough live rock. Live rock IS your filter in a reef... I suggest you work on increasing it to over 1 pound per gallon.
Here is an example: I have a 90 .. in a simple answer... I feed really heavy... I have lots of live rock. My tank is cleaner now that I feed heavy than it was when I fed light. Why, the live rock now is loaded with bacteria. My skimmer produces far less skimmate than it did when I was feeding lite. (warning: don't feed heavy unless you have plenty of live rock and work up the food volume in very tiny increments)
I say this often and I say it again... The magic is in that old live rock!