I have an AquaC Remora HOB skimmer on my 18 modified to fit in the sump. I had it lying around and I tried it and it took stuff out so why not? I empty about a 1/4-1/2" of pretty dark skimmate once a week so it's not a lot, but that would still be there if I didn't run the skimmer, and those puppies are complete no-maintenance. I do 25% water changes weekly as well in an SPS dominated mixed reef with 2 small clowns.