Watered yesterday with the following recipie
When I woke up this morning they looked liked this. All bleached out on top.
The 2nd plant is in a 3 gl pot got the same recipie but didn’t react the same
1 gallon pot
Happy Frog soil
PH 6.0
SF-2000 set to max
Skittlz-auto
Week 8
Nutes
Big bloom 15 ml
Tiger Bloom Buds and bloom 9.86 mo
Cal mag 5 ml
PH down
Humidity and airflow?
Humidity averages 70
Air flow is Small fan
Humidity averages 70
Air flow is Small fan
How far from the light is this washed out top?
It looks like one of the leaves I had that was literally hugging one of my veg lights.
24" from the top. I did turn on a side light that I’d never used before last night
Have you always fed or pH the water to 6.0? That is quite low for soil. For soil, pH should be closer to 6.5.
This eludes me completely. Seems to be some sort of toxicity.
This is very true, and I always worry when I see x.0 or x.5. Sounds like a roundabout guestimate kind of number. Are u resorting to a soil probe style meter? They are kinda unreliable for marijuana growing purposes.
On second read… this stood out. Is that plant closest to the light. And what kind of light is it?
I shoot for 6.0
I use a probe style meter.it is a guestimate. I take the water down to around 5 because the runoff is typical 6 something or even above 7.
Looks like it could be a fungus of some type.
I would say you have a pH and heat stress issue. In FF Happy Frog your PH should be 6.5-6.9 and those leaves looked cooked from heat stress. Have you flushed those since starting the FF trio? That nutrient line is notorious for salt build up in the root zone. They actually recommend flushing every 30 days. When I used this nutrient line I would use their sledge hammer to flush and follow up with their Boomerang and 1/2 % of base nutrients. A PH and TDS pen are critical for mixing your nutrients by growth stage and the nutrient schedule 
The leaf damage we see might be from light burn or heat but I think the underlying problem is pH related. Having pH as far off as you are guessing it is, maybe 5 or 6 not real sure because a probe style pH meter is so inaccurate, your plants are in a weakened state. They can not defend or help themselves. You point out the one plant with the glaring issues, but I see problems with the other two as well.
You must use a decent pH meter. The least expensive good one I can recommend is a Apera PH20. There are many that are $10 -20. Any would be better than a probe style. Just plan on replacing it. You did not mention PPM. Knowing the parts per million of the feed solution and runoff is important. Especially with FF Trio. I have experience with FF because I used it. If you don’t have one, get a TDS meter too.
You have some work in front of you to get to harvest. By the sounds / look of it flush out the soil with pH 6.5 plain water. 1 gallon pots are small even for autos. The smallest I use is 3. Feed them immediately with 6.5 solution. Clean out the severely damaged leaves and get them to harvest. Good luck
Well stated, @Oso1 @beardless gave you some sound advice. The Apera PH pen is a valuable and needed tool as well as a TDS pen (Blue Lab) is what I use for the TDS. Your plants can only take in nutrients in a specific PH range by individual mediums , soil , coco, hydro. Mixing nutrients for feeding should be adjusted for PH and the PPMS. When you look at the FF trio feed schedule, you’ll notice the EC/PPMS they post are high, don’t try to hit this mark with your Trio nutes. Those numbers include other nutrient adds. You should be around 900-1000 PPMs of flowering nutrients and supplement calcium and magnesium, that’ll add about 50-75 more PPMs. When you PH your solution keep it in the soil range 6.5-6.9. Consistency will pay off
Looks like nut burn
The plant is still very moist. Should I wait until it dries, or go ahead and flush it out?
It’s wet already, go for the flush. Do you have a way to test your run off from flushing? If not, it’s pointless
Still the same probe meter. I am looking on Amazon now for some different meters.
U hear it alot. But for good reason. The Apera 20 is worth every cent man.
https://www.amazon.com/Apera-Instruments-Value-Waterproof-Tester/dp/B09CPM2NJJ
The combo kit is not necessary but that pen is a beast. PH meters are alot more sensitive then TDS ones and spending a few extra bucks goes a long way towards piece of mind.
