If you have nute burn then you should flush them asap. Clean all the fertilizer out of the coco. When you flush just use water phed to the proper ph, maybe a little more or less to correct a little. Burn sucks, the leaves still affected wont get better. Your best tool when running soiless just like hydro is a ppm meter or ec, whatever, but also knowing how to use it. Since soiless needs constant feeding you need to know what your really running through the plants roots. Saying im adding five mls of this and three of that just wont work. Read up on what you should be feeding the plant at different stages, i prefer to feed the plants based on size rather than age. I use the size to determine how much food to add. Theres no pic so i cant tell ya what you should be aiming for as far as ppm goes but its a pretty simple routine once you have the hang of it. Over fertilization is one of the most common growing mistakes so live and learn.
heres some pics they 3weeks 3days into veg now mate tell me what u think pls 
