Thats a good chart, not seen it before saved it.
Copper deficiency would have been my next assumption, as that starts on the top leaves, and as I see now, its absorption is blocked by high N according to the chart.
I have been having similar problems with my plants and have high N atm.
It does kind of look like Cu def, but I’m wondering how I could have high N though… All my bottles are low N and the highest EC I use is 1.0 with .3 of that being tap water. I measure run off and it’s never higher than 1.2EC partly because I flush every 5 days.
I do a small flush every 5 days, using tap water and a cleansing agent. My run off isn’t ever high enough to indicate salt has built up 
BTW I’m not trying to argue with everyone or just disagree lol 
I’ve gone through a lot of this stuff already, but I definitely must have missed something because I still don’t have a strong feeling that anything I’ve thought of is correct…
I appreciate everyone’s input and suggestions, genuinely I’m stumped.
My best guess so far is that without a fan between the light and my plants, the tops get hot and pull a lot of water. They absorb Nitrogen in the water, and because they are drinking so much they get some toxicity to the point where some micro nutrients get locked out.
That’s the only thing I can think would make sense of a toxicity when I’m feeding at such low EC with my pH in check. However I’ve not really seen pictures of any deficiency or lockout that look like mine with the bright yellow tips and margins though Zinc and Cu both look possible neither is super similar.
I never got the feeling you were arguing or disagreeing - we are all just tossing ideas at you and you are responding in regards to those suggestions - typical think tank - no egos on the line here lol - just looking for ways to make the plants happier
A slightly different approach has worked for me the past few grows.
When stuff like this starts around week 5 or 6, apply LITFA and let the plants finish. Doesn’t seem to matter in the end - but then again I’m not trying to win the Cannabis Cup.
For sure it doesn’t actually seem to affect bud quality much, but it is a puzzle that boggles my mind lol. It also makes for some pretty gnarly pictures…
I’ve never had “perfect” leaves at finish, but even when I was new to growing my plants never finished looking so wacky.
Not sure if it’s knocking the yield or more importantly the terps, but probably a little bit of both.
Probably next grow I’m back to a more normal approach with less experimental techniques. Hopefully I won’t see it again… But I sort of doubt that.
When I first started growing I was super picky about this type of stuff - it felt like disaster was imminent. At one point I was in a bad mood (for several weeks) and said “piss on it I am not going to try to fix it.” The bud still did what I needed it to do. So now I am lazy with every grow. If it doesn’t do so well with the minimal effort I am willing to make, then too bad - I have plenty of strains that do. I honestly believe that a proper drying/curing process is much more critical than some yellow on my leaves (that just gets cut off). What I’ve come to realize is just how damned resilient these plants can be.
If your temps are on the high side and the humidity is low they will expirate more and uptake more water and nutrients. On the chart N also affects K uptake which is also what pics 5 and 6 look like.
Copper deficiency is affected by light as well, so it may be a combination of light to close and high N causing both copper and K lock out.
Your plants are getting watered and fed 8 times in a 24 hour period, even with low N that could be too much, and reason why your not seeing to much nutrient in your flush is because its all in the plant 
Maybe cut the watering down 25% and see what happens.
As I said I am experiencing similar problems, mine starts in veg, but after they have stretched in flower it goes away, as lots of N is used up quickly. LITFA may be the answer to resolving it, but its better to know whats causing it as well.
I found raising the light was the only thing that helped, after adding more nutrients, thinking it was a deficiency and nothing changed, I thought it was just the light to close as they were new LEDs. Now I am thinking its both lights to close and too high N causing the lockout and a copper and K dificiency, I will see if re potting the plant I have in veg showing the same problem, and see if it improves as I want to resolve this problem as well.
Didint think you were Like Monkeyman said, its a brain storming session 
I’m voting chlorine toxicity.
Pool shock is insanely potent and you’re eyeballing it. Eyeball an eighth, not something you need a few milligrams of.
Make a stock solution so it doesn’t happen going forward. Chlorine dissipates so fast, cut it entirely for a week and see what happens. Chloramine is more persistent, if you’ve been using the Zone recently, do a reservoir change.
I use Dyna Gro, and my plants have never looked like this. Lotta dudes in this thread totally talking out of their ass, careful where you get your advice from.
bruh you use it to sterilize the nutrient solution, not adjust pH lol.
I water my Rockwool twice a day in veg and 2-3 time in flower, I also top feed.
How are you mixing the nutrients???
Protek always goes first
I then add the Foliage pro or Bloom
Finally the Mag-pro.
The Dynagro feeding schedule is pretty HOT so I just feeding them around 550-650 ppm (@500scale) with no problems.
What is you PH and PPM run off?
Are you using RO water or Tap???
It’s a real possibility. It’s the only deficiency/tox that is noted as yellow tips/margins.
No pictures of it in cannabis that I can find, but here is one on another plant:
The thing is though, it’s suggested that Cl tox will affect older growth first which I don’t think is the case for any of the plants affected so far since it’s all on the upper leaves.
I haven’t used Zone this grow, just pool shock.
Just to clarify: The first 4 pictures in the first post are plants grown with only pool shock, and the last three pics are a plant grown with only Zone.
For sure. It doesn’t look the buds were affected too badly, I’d just cut the pool shock, do a reservoir change, and see what it looks like in a few days. Those leaves probably won’t recover, but the problem should abate. I get it though, it’s been hotter than hell lately and that’s the best time to have a sterile reservoir.
I definitely suggest making the stock solution going forward.
I mix like that with protekt first, then base then mag pro.
My ppm in the rez is 500 (.5 scale) and never comes out higher than 600 in run off.
My tap water is 150ppm, and I included it in the numbers above.
Yesterday I recalibrated my pH meter with a 2 point calibration and the rez was 6.1 and run off was 5.7.
I water my cubes about 3 minutes every 2 hours when lights are on at a rate of 1 gallon per hour. So they each get about 1.5 liters of water a day.
If I water less I have to flush more often because the cubes dry out really fast and it causes salt build up.
I’m using gro dan delta 10s.
Thanks for the info!
I think he is saying that bacteria/algae/fungus can cause pH to move around and if you sterilize you tend to stop that.
I personally switched to sterile because bennies cause my pH to go everywhere.
Sterile reservoir is the way, truth, and light.
If you do active hydroponics, you’ll end up doing it sterile, or you’ll switch to another method.
In the old days organic hydro was all the rage for a couple years, but it’s laden with problems, with no benefits, and there’s a good reason no one really does it anymore.
So it’s 150 ppm for tap and 350 ppm of nutrients? That seems very low.
I use RO because tap water cannot hold the ph down, I also ph my water before I add my nutrients.
Are you covering the cubes??? I use clay pebbles to cover mines, they do a great job keeping the block from drying out quickly and they also cover against algae and mold.
(The DIY drip rings were later removed for crappy performance)
I’m with you on that for sure, I only mess with my pH once a week now usually during rez change.
What do you use for sterilizing and what dosage?
I usually do protect then pH down then the other nutrients.
Yes only 350ppm of nutrients in the rez (on top of the tap water).
I cover my cubes with flora flex caps:
Bleach. Pool shock is undeniably cheaper, but a $4 gallon of Clorox will still last years and it’s already in solution, so that’s $4 worth of work, easy.
I use like 1mL/gallon about.
