I lost everything !!

[Bob I]

It is indeed sad to hear of your losses, but you need not blame yourself. I have lost corals when they were moved to a new location within a tank. I have even lost corals when a snail knocked them over during the night and I did not notice it for a couple of days. It sounds as though some pieces died and released toxins. , and from there it snowballed until the whole tank was polluted.