I believe Fuel was into SPS thus the need to have Ca reactor.
Lots of stuffs can contribute to corals shrinking or dying. Yours might be due incorrect flow but another reefer might be due to water params.
Ionic Imbalance will affect all livetsocks in our tank. Simple because all of them depends highly on the water to carry oxygen, food, regulate temperature or even hydration. When Ionic Imabalance happens, it means that the KH and CA and even PH will go haywire - this will induce stress and even death.
Imagine what will happen to some of us if we were to drink ice cold lime juice once moment and hot milk the next moment - sure LS wan (for LS I dun mean Livestocks)