SkunkXL Third Grow!

First week of flower, and the frustration is still going on. We have no idea whats wrong with the plants. This is the third time we've grown them, and we haven't changed anything that should lead to these stressed plants. We only water when dry, the plants have fabric pots and good run off, so over or underwatering is most definitely not the issue. I checked the PH, its 6,3, which should also be fine. Somehow 1 plant looks worst, 2 look mweh, and 1 looked okay ish. The leaves of 3/4 plants are lighter green then we'd like to see. All plants show more or less of the drooping leaves. The leaves are also very narrow, and a bit curled downwards. The temperatures are very constant, ranging around 18C at night to 23C during daytime. Everything seems like the plants should thrive, yet they don't. Could this be disease? I'll start another growquestion as the symptoms have evolved and we still have no idea what is going on. We'll monitor them closely and will provide update next week. For the people that came here from the growquestion, thankyou for reading the problem in the diary! :)