I agree with max, i have also used it and it seems real weak. Plus the only thing your getting is calmag, with botanicares the is a NPK ratio.. Now I'm stating this for soil, it might work much better when used with hydro. But i'm a soil type of guy
actually the more I look at the pics, it looks like the needed to be watered and you didn't water them in time. Plant got shocked and never recovered. Give it a good flush and see what happens but the outlook looks bleak.. sorry for your loss