Ah okay thank you for clearfying, currently it's running a reactor with GFO and carbon. I don't have a fuge or skimmer set up on this tank as I have heard mixed things about the skimmers on this size tank. I may have to take a look into them again if that will help.
I started with a nano as well, some sort of nutrient export is necessary. Skimmers for small tanks didn't use to be all that great, but I havn't done research on them in many years. That said, growing macro algea, a skimmer, algea turf scrubber, or very regular (and properly sized) water changes are critical to export nutrients. Water changes have the negative of affecting alk/ca/mg levels. Macro algea would require some sort of fuge. Small skimmers use to be a nightmare to adjust (again, bon't know about today's offerings.) Every one has negatives. If your using test kits like API, red sea or similar, for po4 and no3, they aren't accurate. If they register any no3 value you have a lot which will eventually cuase one problem or another. GFO as long as it's regulary changed and not clumped up will take care of your po4.
The other option is to keep hardier species that can tolerate the high nutrients. You may just have nusciense problems, like you have today. It may be eaiser to just regularly blow it off with a turkey baster or siphon with a tube.
