Pineapple Express

Well, sometime after 3/9 the girls really took a shit. IIRC, I watered each solo cups until a little runoff came through. Maybe 4-6oz per cup thinking they would dry out sort of quickly. Think I overestimated. As far as the light, it is under a 720w 8 bar but the light is only at 50% and Photone is showing 400-500 PPFD. Light was maybe incrementally increased during that time to up the DLI by 1-3 points on the top colas of the flowering plants in the same tent. The plants have been under the same light the entire time. It was suggested that this may be a light intensity issue for them. I had been thinking maybe root bound issue or pH/watering problem but I have only watered them twice, maybe thrice.. during their lives. I am use to providing water sparingly in big pots. All 3 showing the same signs. Planning to move them to 3x3 under the MIGRO 3 light once the Lemon is done drying and can be taken out. Becomes apparent in these situations that I should have documented each watering. *Edit* Recalibrated my Apera PH pen. Feeding water is still within the correct pH range (5.8). Will have to double check it against the dropper test.