Probably true, but I can tell you that the response of the corals to the switch back to Instant Ocean was quite dramatic. All of my montipora had stopped growing, and each water change with Reef Crystals seemed to further aggravate the situation. Within a week of going back to Instant Ocean, all of my corals began to grow again, and by the second or third water change with Instant Ocean, they were growing rapidly again. All other water parameters were the same this time (from what I can tell by measuring alk, pH, temp, nitrates, phosphate, iron, potassium, magnesium, and iodine).