do i really need a protein skimmer? ive got a fluval g6 filter and would like to get rid of the skimmer if possible. my tank is about 240 litres please help

If you have marine tank using the 'berlin' filtration standard then you do need a protein skimmer. However you would not need a powerful external filter with biological media in it.
Other marine filtration methods vary as to the requirement of a protein skimmer.

If you have a freshwater system you generally don't need a protein skimmer.