1 Girl 1 Shed - AK Feminised

Well what an interesting week.... My own guilt enticed me to add another bulb, bringing the total CFL watts used up to 112w (6944 Lumens)... which for a 40cmx40cm tent should be ideal! Realised I have been seeing a few fungus gnats flying around inside the tent, after looking closely at the top layer of soil, I saw dozens of small larvae wriggling around! Damm'it!!! Scooped the top 1/2 inch of soil off, added a layer of dry perlite and then strategically placed a pot of cider vinegar/soap to drown the flies. 5 days into the week, started to see all the major fan leaves start to turn yellow and mottled. Instantly thinking this must be the natural process of losing chlorophyll before harvest, as a result I started to flush out the soil. Still flushing a few litres every other day and now looking at the fan leaves the yellowing looks more like a major nute burn from a lockout.... If anyone can identify the burns, let me know... I have no idea if this is natural slow down before harvest or a major nute lockout/burn... Probably cut her down after 5-7 days of flushing (or longer if the burns stop), don't want any of that fertilizer in my lungs!!!