Reef crystals or sea salt? And also it may be possible that your water changes don't have enough nutrients to keep the amount of Coraline you have to thrive. It's possible you could benefit from doing more frequent water changes or dosing to keep your parameters to a suitable level. Meaning alk, cal, mg. Ect. Aswell as the light you turned down. If you noticed a change in Coraline after you dimmed your lights, that could be it too.Every 2 weeks, 10-20 percent. InstantOcean salt
I think the fear of hitchhikers is largely overblown. I can’t imagine having a reef tank without all the microfauna and hitchhikers, to me without them it’s not a reef tank, it’s a coral display tank.Lol. I am afraid of hitch hikers. I do have 3 real live rock in there, to seed things.