Canister filter ?

I have a 75 gal that has the sump rated for it with a protein skimmer.i also added a magnum 350 canister with activated cabon in it.i think it helps alot with floating derbis and fish waste.my water is crystal clear and fish are very lively and happy.my water test levels are perfect and i havent done a water change in over a month.i feed twice a day too.i change the carbon and clean filter every month.i clean the overflow box sponge every week or few days.i clean the sump filter every 2wks or month depending on derbis.all my live corals are fine too.so i would have to say if you have the canister already it wouldnt hurt to add it.extra filtration and water movment is always good.