Freshwater filter ???

Hi all
I have a 56 gallon with an overflow and a wet dry.
My problem is i dont think im getting enough filtration with 2 ocars and pleco.

Lokking for a recomendation for a new filter, or maybe a fix of some sort, i was looking at possibly going with a canister?

 

I use a Rena Filstar Xp2 on a 46 gallon tank and have been very happy with it. It is very quiet, has good flow, is easy to clean, and does not have to be reprimed after cleaning.

 

well ive since added a couple plants and a chorcol pouch, and bam! no more amonia, at all so maybe a new filter can wait

 

so i have a ? about my current setup pictured above.

how should i have that set up? for fresh water
Right now i have my incoming water coming into a feed box flowing over floss with carbon under that then falling over my bio balls then out the bottom over the over flow and to my return pump.

The reason i ask is becuase i plan on making a new one from 20 gl tank for my 56 gallon tank and adding this to my 90 with a canister and a DIY weir

 

i always use canister for freshwater setups, all nice and sealed up, can go overkill on the size and it only gets better in my experience

 

well the 90 gal i am setting up has a fluval canistar for it and ive thought about adding a sump as well for added filtration, but my 56 has a sump on it now, the one pictured above, and it seems to do pretty good. I was just wondering if i had the right set up for a fresh tank cause i would like to make a new one