Ive had that problem with soil and suddenlydropping ph.I lost a real nice afgan
to that.the only thing I could figure out as the cause was a lack of a good buffering agent.My ph tanked and actually got hotter as i flushed,that sounds
alot like your problem,the signs are seemmingly apparent with any kind of ph problem high or low ph if you have this type of leaf curl you more than likely always have a ph prob,which as in my case with the afgan alot went wrong
real fast when I couldnt raise it fast enough.Ibabbleatimes:stoned: