SOS yellow leaf lighting green color

Hi i have got a big bang auto strain and i have this problem in 2 plant another 3 is have a little bit yellow tip.
please help me give some option to define the problem. I think its a little note burn, but i can't believe because i use plagron lag Bloom nute. yesterday i give a half dosage of bloom fert and a little superthrive and a little plagron forte. 3-5 weeks left to harvest. Here are some pics.

looks like an N def. is there any N if your bloom fert? could be your MAG in this case a vitamin pill disolved in water will work fine. i might up the dosage to 2/3 strength or full strength soon.

yes it has NPK6-12-10 only the upper leafs are problematic. The lower leafs are healthy.

calmag or add half a vitamin to the water pH and water normally. lay off the superthrive all together during flowering trust me it problematic and can slow down flowering and lower yield i have done too much experimenting with superthrive its really good for veg bus bad for flower
then after a week give em full dose of nutes

if it was N lower leaves would be falling off

the smallest older leaf lower are yellowing and falling off but its normally i know. Sry for my english. I know yesterday was the last watering with superthrive. next week i want to use bloombastic and i want to fix this problem before.

yeah thats normal they just need some micro nutes. sound sliek your good to go man. and your english well its fine im american so i know my english is shot to shit

only the upper leafs are problematic

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Sounds like light/heat burn , what are the lights?and the temps?

thanks i think the next watering is Ph 6.5 with some alga-a-mic and some plagron forte these are vitamins and maybe it will recovery my plant.

lights are 200w envirolite cfl the temp is 19-21 night and 21-23.5 when the lights on. The humidity is 45-55. in one flower the leaf is touch the bulb and dryed but the problem is a yellowing and some brown spots but its not to big this is why I'm think its overefert a littlebit.

over fert= brown burns and dark dark green coloring on leaves almost overnite in most cases

week off nutes then a week on full blast then a week off then back on best way to fertilize with synthetics or in other words every other feeding add some nutes, its good to wean your way to full power so if you think you might be overfert just keep the nute dose the same but skip a feeding

polyarcturus said:

week off nutes then a week on full blast then a week off then back on best way to fertilize with synthetics or in other words every other feeding add some nutes, its good to wean your way to full power so if you think you might be overfert just keep the nute dose the same but skip a feeding

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okay thanks i think not much left with the other plants.