Hi stra8outtaWeed, thanks for your quick reply. I do have Geolite expanded clay balls covering the root-rite cubes and the nutrient level is about 1cm below the bottom of the baskets. I initially thought that it might be overwatering but thinking things thru, I can't see how it can be, especially as the other lady is looking so well... Could the daytime/nightime temp difference be the culprit? Just realised my sick girl is quite close to the air intake duct...
So much to learn my friend!