For nutrient export a small fuge is not the way to go, there´re plenty of more effcient ways to do so eg. cheato reactor
Are you open to the idea of a linked/display tank? You can double your water volume, have nutrient export, lots of pods and a second tank to watch! (sorry, always making excuses for setting up another tank)
Why not a simple sump as a dedicated fuge?
Maybe start your own pods and phyto culture, the cost of putting it together is very low, maybe the first strains culture would be the most expensive thing of all the setup, after that it´s all good... you add phyto and pods as you see fit
but i left my first option for last: take a look at Santa Monica´s Hog scrubbers, you can make one on your own and it´s not a sore in the eye in the display if it{s weel designed.... an uplow in tank scrubber is very efficient regarding nutrient export, also helps stabilize you ph, excellent pod shelter and the algae can feed your hervibores
sorry for the broken english, not native speaker here, hope i heleped!