I would invest in a Tunze skimmer, also a smart ATO. What kind of water testing kit do you have? I'd go with the Red Sea or salifert. It's the most accurate. API is garbage. I just switched over to Aquaforest Salt and new ocean revive T-247 LED. My corals are blooming!!!!!!! Key to keeping a good tank is alkalinity, calcium, and magnesium. Those are the three major things you need to be testing. You have a small tank so the nitrates will always be there. Also you need to use RODI water, if not you're wasting your time and your money. Key investments are skimmer, RODI, auto top off, and test kit. Also a good wavemaker.