Skunk#1 + Zkit Kandy Dreamz Indoor LED Run V3

This appears to be a nutrient toxicity. Since it’s starting at the top and I see your leafs are very dark green makes me think you have been over feeding. I suggest you flush your media out with pH adjusted water at the rate of 1-2 gallons per gallon of soil. This will remove any build off of nutrients in the soil that have accumulated over time. Remember when feeding you need to have about 20% run off out the bottom to wash away the old salts so they do not build up. I hope this helps.

Overfeeding mate. Lower your feed. You dont need a total flush. Just add something that will lower the ph around de roots that will increase nute uptake. PH if not organic needs to be In the area of 6.7 this will allow for peaks and lows. Its the optimal soil ph 5.8 for coco/DWC.

Not lights, but generally way over fed and suffering from a zinc deficiency. A dose or three of soluble trace elements/minerals mix (available from any decent gardening store) should help with the yellowing. But you are feeding them too often or too much........or both....... generally.