Fish disease prep has amazing documentation across sites and going back years searchable online.
any customization of the process leads to population wipeout within eight months on average. Watch for just today alone the # of new help posts in the disease forum
click on the posters avatar, select find all threads
check their initial build, it usually shows how they cycled and added items that weren’t fallowed, such as the live rock I had you buy from petco so we could boost up your corals/ great job it’s working too.
you can see the arc of their system built in those posts, bio security risk items added, most will have a tank at eight months mark when posting for help. Case in point:
https://www.reef2reef.com/threads/fish-dying.956614/