Want to replace my skimmer

My tank is 110 gal in wall setup with sump,protein skimmer located behind wall. Have a coralife 33002(125 gal) skimmer hanging off the sump container right now. Doesn't seem to be cutting it anymore. I have removed all bio balls and run the water coming down from the tank through 10 micron filter material which I clean/change each week. Also run water through a carbon filter which also hangs off sump container. Had my nitrates down to zero for awhile, but then I added a wrasse to the mix. Love it but goodbye invertebrates and hello nitrates around 10.

Looking for advice/experience on replacing the skimmer with another unit to hang off of the sump container. Also how many gallons/hr should I go with?

Hornet

 

With your bioload you should aim for something around 200 to 250 gallons.
You could go with a second HOB skimmer if the sump is large enough if they are not made that large.