If possible I would add some wild or maricultured live rock (maricultured is limestone that has been left in the ocean to grow various organisms that can't be stuck in a bottle). If that's not possible network with some local reefers and see if you can get a few pieces of rock from an established tan that hasn't had any obvious problems in a long while. For the most part bottled stuff is fine but there's alot more going on than just basic nitrifying bacteria. The cryptic sponges, for example, have been found to be crucial for the health of reef ecosystems.
FWIW, I haven't had a mitrate test kit since the 2000s. Alklinity is the one I test for most and I like API. I also use API for pH and Calcium. I use both Nyos and Red Sea for PO4 and Nitrate.
I would swap out a pair of grammas for the chromis, they're prettier, have more interesting behavuor "yelling" at each other and swimming sideways or even upside down and will likely live a lot longer than 3 chromis would.
This is a huge data bomb but these links by researchers might help you understand a little better what's going on in reefs. But as compicated as reefs are my "secret" to success is patience, water changes and manual removal of nuisance algae and urchins. Did I mention patience?
"Coral Reefs in the Microbial Seas " This video compliments Rohwer's book of the same title. Used copies are available on line and it may be free to read on Internet Archive. both deal with the conflicting roles of the different types of DOC (carbon dosing) in reef ecosystems and how it can alter coral microbiomes. While there is overlap bewteen his book and the video both have information not covered by the other and together give a broader view of the complex relationships found in reef ecosystems and are an excellent starting point to understand the conflicting roles of Dissolved Organic Carbon (DOC, aka "carbon dosing") in reef ecosystems.
Changing Seas - Mysterious Microbes
Microbial view of Coral Decline
Nitrogen cycling in hte coral holobiont
BActeria and Sponges
Maintenance of Coral Reef Health (refferences at the end)
- YouTube
Optical Feedback Loop in Colorful Coral Bleaching
- YouTube
DNA Sequencing and the Reef Tank Microbiome
- YouTube
Richard Ross What's up with phosphate"
- YouTube
response.restoration.noaa.gov