Nano's are so much more challenging, as most view as a good starter tank,they are not, things go bad fast and stability is hard to achieve. i would run carbon once in a while but with the chemi pure you shouldnt need to. yea do small water changes you dont want to completly clean out the "good stuff" in the water, keeping up with top offs helps since evap is quick and in such a small aquarium makes things change fast. upgrading the pump in the back helps also if you dont want to add a nano k but the new nano k comes in 2 versions and the smallest one would be great for your tank.you have macro in the tank that should help, i never went to the fuge option but i kept alot of macro in my display.