Hi everyone! Thought maybe someone could share their wisdom, as I am out of thoughts this time. This is my fifth coco grow. There have always been some yellowing problems in past starting seedlings, but never this far into vegetative growth. Plants: 2 x dinfem Original Amnesia fem. Both plants 21 days from sprout (as you can see one plant is behind in growth for some reason) Medium: 100% Canna coco Professional Plus Feeding: Hand watering every other day with tap water PH 5.7-6.0 (water stays 1 day in room temperature and PH brought down with vinegar before feed). 10-20% run-off with PH 6.0 (Also 2 times I let them almost completely dry). Using canna coco A+B 1.2 - 1.5 ml / Liter . As this seemed first typical cal-mag def I foliar sprayed them with epsom salt (5-6 times). Also added some epsom salt to feeding water. Stopped giving epsom salt 4 days ago, as this didnt seem to help. Light: First used 125W CFL, but as I got my first ever HID system going, now I use 400W HPS (Superplant Agro for veg and flowering, 30% blue spectrum added). I plan to use this light to the end. Light is 18 inches=45 cm away from plant tops. Setting: 1 x 1 x 2 meter grow tent BlackBox Silver. I have two fans blowing in tent constantly (1 straight to plants, other straight to light bulb) Temps: 89-90F (30-32C). I know not ideal, but I have grown in past with this this temp. No big problems As you can see from photos the older leaves are browning and die. New growth first seems green, but after 1-2 days yellowing starts again. Also the smaller plant seems more affected by it, stunted growth. PS. I also did a full flush with PH-d water 6 days ago (I fed them too much: 2ml A+B). After flush things seemed greener for a while. But now the yellowing is back.... Thanks for your thoughts!