I have a 55. I feed heavier than most because I have an Angel and a pair of Anthias. I also have crushed coral . I really take care to vacuum my CC every other week.
Recently my skimmer stopped producing and I told my self for 2 weeks: "I'll clean out the injector tomorrow" well, my levels rose, my corals started to withtract and I am dealing with an outbreak of cyno
I've learned that you've got to get the nasties out. It's a full time job.
Good luck, keep up the water changes and I wouldn't add anymore livestock.