Sounds like you used "life rock" that's just been treated with nitrfying bacteria and not actual maricultured or wild live rock. You've bypassed the initial cycle but using "life rock" you haven't introduced cryptic sponges and a host of microbial stuff essential for establishing healthy microbiomes and significantly reduces the "uglies" during maturation. Research has shown less than 2% of the microbial stuff can be cultured and stuck in a bottle so I'd encurage you to get at least a few pieces of maricultured live rock, there are several good suppliers online (I use gulfliverock.com).
Here's some links to research on microbial stuff and nutrients you may find interesting. I find myself often going back and reviewing them.
"Coral Reefs in the Microbial Seas" This video compliments Rohwer's book of the same title (Paper back is ~$20, Kindle is ~$10), both deal with the conflicting roles of the different types of DOC in reef ecosystems. 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
Changing Seas - Mysterious Microbes
Nitrogen cycling in hte coral holobiont
BActeria and Sponges
Maintenance of Coral Reef Health (refferences at the end)
Optical Feedback Loop in Colorful Coral Bleaching
Optical Feedback Loop in Colorful Coral Bleaching / Curr. Biol., May 21, 2020 (Vol. 30, Issue 13)
Richard Ross What's up with phosphate"
What's up with phosphate? by Richard Ross | MACNA 2014 Ty for all of this wonderful information.