It only happen to those so called "reef salt" such as Red Sear coral pro and Reef Crystal. Both have insanely high alkalinity and calcium than salt water can hold on to.
I stop using both a long time ago as they are not good for some acropora, especially the dragon acro, red dragon, green dragon, pink dragon, rainbow dragon...one dragon, two dragon, dragon that can drive a car, dragon that can't walk too far...