tip it upside down and gently wiggle the whole coco medium out if you can, but try and be gentle, see if there is any tinge of brown there. then replace back in pot.How do I check the roots without transplanting?
How high should my light be, 400w MHRaise the lights, let it dry out and re-start with the feeding at low dose. Bottom little leaves like that are supposed to die away. Concentrate on new growth.