Tell us more about your tank and you husbandry. What are you feeding your corals?
Just a little bit about what I am doing. I had begin slacking on my husbandry and picked back up on it. Every 2-3 week I do a ~50 gallon water change using Red Sea Coral Pro salt. I feed my fish 2-3 time daily. I use frozen mysis, Formula Two Flakes, and New Life Spectrum pellets for the fish. I try not to feed the same thing in the same day. On feeding, I feed in the morning/lunch/evening (if I don't forget).
As far as feeding the corals, I do not do anything consistent with feeding them. Every once in a while I will put in some Oyster Feast. A few squirts and that's it.
I think some of my success with growth if doing my water changes every 2-3 weeks, having 4 Hydra 52 LEDs over the tank running a 12 hours cycle from 10AM to 10PM with the peak around 2:30PM at 100%. Here is a screenshoot of my lighting period (the same for all 4 LEDs):
I have 2 Vortech MP40wqd (Left/Right) and 2 MP40wes (Back Left/Right).
The graph for the L/R is below:
This is the graph for the back left/right:
So I have some serious circulation going on. Add to that my dart pushing out a lot of flow as well and you can see that flow is definitely not an issue. Sometime maybe too much.
Also a little secret for the late Al Armour was to put the zoas that I want to grow in a high flow area. His words were that they will try to get the heck out of the way of all that flow and start doing the only thing that they can do is grow to move. The flow isn't too much to make them close, but maybe having good flow to keep their skin cleaner helps.
When introducing any new additions to my tank, I do a Bayers did for a few minutes to make sure I am not introducing any hitchhikers that would harm my corals. Even if I did get something in the tank, I will handle it like everything else in the hobby, slow and methodically.
Had a GHA outbreak when I slacked on my husbandry and rather than buy chemicals to remove it, just used hand and a scrub brush and identified my issue with phospates and resolved that. Now the GHA is under control and dying out.