Give it time. Not only is the bio-activity in your tank low as yet, you haven't, I'm assuming, made your ritual share of new-tank mistakes, like the classic topoff accident, temperature adjustment snafu, overdose of something, salinity rise, water-change foulup, etc. It's like learning to drive a car. Don't take the system onto the superhighway until you're sure and steady. You could start a tang into quarantine---that's 4-6 weeks in a separate barren tank under carbon filtration with frequent water testing; learn to manage your system, run your requisite tests, and above all be sure that wild-caught tang isn't bringing little passengers in with him who will multiply in your tank and do great harm.
