The yellowing on the edges of the leaves, is it nu...

That's an early stage of potassium toxicity (leaf tips and margins burn). It probably is the strain that likes less nutes. I would give less PPM, 20% less I think. Good luck.

Yes sir that is the very early stages of nutrient burn ! My advice to you would be to decrease the dosage of nutrients by a little bit . Your plant is very young and to go almost full strength with it right away can be to much sometimes. Also I'm unsure if you are giving nutrients on every watering if you are i recommend you stop doing that and only give it to them every 2nd or 3rd watering . This will prevent the root zone from getting to hot because it can't absorb all the nutrients you put in the medium at once also with giving it PH corrected water in between nutrient feedings you can ensure that the plant will try and use 100% of whats nutrients are available in the soil at all times . Humic and Fulivic acids will aid in the healing process of this light nutrient burn you have here , you've gotta remember that w.e you see on the top will be on the bottom as well . So that means were you see the light burns on your leaves is also were your root zone is being affected . I would also try raising your PH your optimum ranges are 6-6.3 in coco I find that 5.8 might be a little to hot for your root zone but thats up to you. All in all your in good shape I would just decrease the strength of the nutes by a little bit and reduce the amount of times you give them nutrients as described above and your plant(s) will spring right back into shape <3 . I hope this has helped you on your journey -Happy Growing!