I don't have a definitive answer either but here is a guess. Low ph blocked the nutes in addition to whatever else it did. From the the size of the those "pots" perhaps your plants need them since I don't see alot of extra soil for the roots etc..---flushing removed even more of the nutes. If you are desperate try watering them again with nute solution--ph correct of course. Also would misting them be an idea as they are clones or not? Afraid clones are not my strong point.