I have the surf4 in my high-nutrient eel tank. It works but not, in my experience, as well as they advertise. If you have room for a chaeto refugium, it will do a lot more for you. THe nice thing about the surf 4 is it's small enough to float in the sump beside a protein skimmer which is what I do, but ultimately I plumbed in a refugium and that did the nutrient export trick for me (and it's way cheaper).