Please help! Nute burn or deficiency?

[TrillZilla]

My friends plants are yellowing but I can't tell if it's nute burn or light burn

 

[Ninjadogma]

I'm thinking it's your light. Notice how those underneath leaves not exposed to it directly look beautiful. If your light is dimmable, you might dial it down to a lower percentage. If no dimmer, you can raise the light higher. If you have a typical smart phone, you can download the Photone app, take some readings at different distances. A plant that small you really only need about 400-600 ppfd. The light manufacturer should have a chart to show what the ppfd output should be at different distances, but you can check what the ballpark reading is with the Photone app to see if you're in the same general neighborhood.