Deadstill said:

Leaning towards sulfur deficiency, but hard to tell from those pics. Can you take a couple of the whole plants? I see some other leaf damage in that first pic that concerns me more than what I see in your new growth.

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Homesteader said:

The veins of your leaves are yellow which often indicates something is going on with mag (whether it is getting to little or too much of something else and it is locking out is a differnt story.)
What is you pH? If I was a betting man.

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Homesteader said:

I think your pH is too low.
Mag and calcium along with twisted shoots.

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Homesteader said:

Take for what its worth, I don't do hydro but I assume it is related to your water. Where is your source?

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Anthem said:

It has something to do this the Gavita LED's. I have been running them for about 18 months and they always are a challenge. Like the lights, but

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Anthem said:

I have seen the same thing many times. What I have been finding out, I say finding out because I am still learning about these lights.
#1. They produce a lot of light so the plants seem to want more food
#2. I have had a nitrogen deficiency and I have started to add slightly more nitrogen to the nut's and that has helped. Not sure if it is because of the lights or nutrient line (floramax) in regards to the nitrogen issue.
#3. Have to really what the amount of light the plants are getting, slowly bump up the light to full power.
Also I saw some dark top growth in the second picture. It could be the beginning of light burn or something else

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Anthem said:

It starts with the purpling of the stems and the light yellow veins in the middle of the leaf's. Honestly, I believe is has something to do with the amount of nutrients the plant is getting. Last run I peaked at 1800 PPM's in soil and I saw little or no yellowing of the leaf tips. I have two areas that I can only fit a smaller plant. I usually use those 2 spots for minor experiments. This last run I threw in a couple of sluricane plants. I have ran this plant before and I got just to the edge of lock out at 1200 PPM's. Same food, same soil but Single Ended HPS. So I have some data that suggests under the Gavitas the plants want more food. You will find that the purple stem is a deficiency of P and I believe the yellow vein is a N deficiency.
There is going to be people calling all this BS and I understand, but there is something with the Gavita LED's. I am also running the Growers Choice Roi-E680 and I have the same issues. basically the same light. With the Growers Choice I am 2 1/2 weeks into flower and I am not having any issues. I vegd the plants in another room and they got dropped in at about 18inch tall. I did not drop the lights they stays at 8' and I started the plants at like 50 percent intensity and started bumping up the lights a couple percent here and there. At one point I had the light intensity too high and I had to drop it back like 6 percent. It was close but no light burn and the plants recovered. Right now the plants are about 24" from the lights and about 90 percent of intensity. Totally green and healthy. PPMs are at like 1200 and no complaints. Also I do add nitrogen to the mix. I am using verde by hombolt and that has really helped bring the plants around. Be careful with that stuff. I only add 1 ML per gallon. Anything above and the plants will start getting nitrogen toxicity.

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Draumo said:

Yep, same thing. Early purple stems, yellowing in center veins, and then wispy curly new growth. This is with 4' off canopy and dimmed at 50%.

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Anthem said:

The plants are pretty small. I would honestly try lowering the intensity to like 40percent and a good all around feed. You might be surprised by the outcome.

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