Auto Girl Scout Cookies

Absolutely explosive growth from last week! I'm completely shocked. Apparently the grow light is massively more effective than depending on the sun this time of year. And to think 2 weeks ago I was really disappointed and thought this was done growing. Don't think I'll ever depend on the sun again for growing. Noticed some of the fan leaves started to turn pale green or lime green from dark green, so I'm thinking it could be light burn, nitrogen deficiency, or just regular aging. This is in a 5 gallon pot of Fox Farm Happy Frog soil, which is already nutrient rich and probably an overkill size pot for an auto, so I'm thinking it's NOT a nitrogen deficiency, but just to be safe I started adding Fox Farm Big Bloom at 1/4 the recommended strength every other watering.