Okay so, I've 2 months in with a light pattern of 18/6 with a 600w MH setup. Im monitoring the ph of the water and using natural spring water. But still, yellowing and burning at the tips. I keep light around 16"- 18" away. I gave it cal-mag for the last 2 weeks using it once every two waterings then once every three. Im attaching a few photos to show you whats up.