Nute burn in flower at low ppm?

hey everyone, this is my first grow (please let me know if I should post elsewhere). here's my situation:

growing in 100% canna coco under 2 300w LEDs.
DTW.

running canna a+b nutes at about 350 - 400ppm with tap water (120ppm) + calimagic @ about 100ppm.
have run a seaweed extract at low dose for most of the grow and they seem to like it, the roots look great.
also cannazyme week on week off. ( I have lowered the dose down from about 500ppm of a+b a week or two ago because of nuteburn(?)

ph 5.8
runoff PH about 6.3, runoff ppm about 480ppm
watering daily with 20% runoff

2 NL autos

week 1 flower, 37 days from seed.

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Anyway, just before flower kicked in I started noticing what looks to me like typical mild nute burn (not sure though) the plants are fairly dark green and most leaves on one plant and some on another (not just affecting new or old growth, seems random) have yellowing tips (just the very tips mainly). some new growth is coming out with like half yellow leaves, and some is fine. seeing as my runoff ppm is so low and my feedings aren't very heavy, does anyone have any idea what the problem would be here? I'll upload pics when lights come back on....

+ i also have a PK boost to use, but atm im too scared because I dunno if im over or under feeding...
also lights are a foot or more away

UGivxx said:

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Anyway, just before flower kicked in I started noticing what looks to me like typical mild nute burn (not sure though) the plants are fairly dark green and most leaves on one plant and some on another (not just affecting new or old growth, seems random) have yellowing tips (just the very tips mainly). some new growth is coming out with like half yellow leaves, and some is fine. seeing as my runoff ppm is so low and my feedings aren't very heavy, does anyone have any idea what the problem would be here? I'll upload pics when lights come back on....

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cant..notice the looks, not sure, seems to be guesswork without pictures

chemphlegm said:

cant..notice the looks, not sure, seems to be guesswork without pictures

Click to expand...

Yeah, will post pics in like one hour just curious though, nute burn possible at low ppm like 500 total? I don't think it's too severe anyhow

Pretty bad photos but hopefully you get the point

relax man those look stellar! up that ppm and prove it to yourself. follow directions on the bottle carefully.
nice job!

show off

haha thanks man thats good to know.
so theres no chance im burning them at that low of a ppm?
ive actually just tested my PH pen and it was about .2 above what it should have been so now i'm thinking its probably that causing it...

I couldnt say what's happening, keep on watching, learning and all will be fine

UGivxx said:

View attachment 3944065 View attachment 3944063 View attachment 3944062 View attachment 3944058 View attachment 3944060

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Your lights are too close. You can see that the serrated leaf edges are up, meaning they are expiring water faster than it can suck it up. I'm guessing you're watering frequently. Heat stress also does this.

Whats happening is the plant can't pull up just water to cool it off, it also brings up all those nutes, in a relatively short span of time. Thats whats burning the tips. Then it starves after that. You won't hurt it by feeding it. Until you get that heat down and those lights at least 18 inch from the average canopy level, you are going to have that nute burn.