First time grow - Green for lockdown

Another positive week of growth down. She is really starting to smell now tho! Not an overpower weed smell, more like fresh cut grass mixed with citrus, so its definitely pineapple express 😄👌 I have been monitoring an issue with large fan leaves on the main cola for 2 weeks now, which almost overnight has become more prominent. I will raise it as a question below. I have a few idea's as to what might have caused it, but since its only 2 old fan leaves I'm not too worried. So starting this week I have changed a few things in the setup. The 600w bulb for 1 plant was just too much, so I switched it for a 250w bulb and moved the light a lot closer. As I am running a cheaper light and closer, I have also decided to up the hour of light to 20, potentially increasing to 24 later in flowering stage. Interesting to see what affects this will have on the plant but I am hoping for no change at the least. Thank you again for another helpful week on grow diaries and I will keep all progress for the week up to date. W4D1 - She's bulking up and starting to smell now 😁 Yellowing fans leaves issue has made a jump tho so guidance will be needed. W4D2 - New light in and no noticeable change in behavior as yet. W4D3 - Yellowing of the leaves has increased. The 2 affected leaves have degraded and 2 more of the old fans leaves have began to turn. Still no resolution. W4D4 - She still looks perky and is still developing, but the yellowing is increasing in other area's. Mostly still on the main colas but hints in other area's now. W4D5 - So I have begun the process of flushing the plant and soil. Potential issues are nute-lockout, potassium deficiency, PH in-balance or a calmag deficiency. Yellowing is spreading, but slowly. After flush and ph balance water for a few days I will reintroduce nutrients at half the recommended. MORE HELP AND GUIDANCE IS NEEDED.