I know growers who use wormcastings & guano ,they can go from start to finnish without adding a drop of additional fertilizers,giving half of what you fed them(every 3rd wattering?) every two weeks would've been more than adequate,you flushed ,and still no improvements,is there any foilage left or any new growth at all ?,If they seem to be getting drier with no signs life,they probably can't be salvaged,try flushing again to about 600ppm,then wait and see if it responds,there is no quick remedy at all for your situation,only time will tell,give them only continous fluorecent lighting for now(about 160WTs),i wish i could help you out more,good luck....bonbon