I would say it's the shrimp they can pick at coral you may want to take a close look at them are some times confused with camel shrimp which will eat coral
I have two fathom LEDs over my 90g they are by far the best lights I've owned awesome growth never had a problem with them and if you ever have a question the customer service is outstanding fathom is a stand up business I couldn't be happier
I've used ultra life red slime works great no effect on my lps or nem, I've had problems in the past with outbreaks because I waited to long to change my sediment filter in my to unit