Hi. I'm running these clones in coco/perlite. Ph about 5.9, using cal mag, epson salt, and general hydroponics flora nova series grow.
All leaf tips are yellow with some burnt. I'm in a 3x3 tent with a fc 4800 at 50%.
Are you running nutes at full strength? First notice is too dry for coco. Think of it as hydroponic medium, not soil. Occasional dry out of coco is ok, but should be watered to runoff often.
You are doing a good job friend. BurntBacon is right you need to keep it a little wetter and with less EC. They should pull out of it soon and grow like crazy.