Plants dying in DWC, any help appreciated (w/ pics)

I have two plants in DWC that are about 3 weeks from seed. The lower growth keeps yellowing/dying while the newer growth looks much better.

I'm using Advanced Nutrients PH perfect 3 part w/ RO water. PPM was about 5-10 before adding the nutrients, now its around 400. (2ml per gallon of each of the 3 parts) PH stays around 6.2. I haven't added anything else per recommendations from AN. I have a 400 watt led grow light about 30" above them.

Each plant is in it's own bucket with w/ its own airstone. There is also a reservoir with a circulating pump that runs 15 minutes of every 60. The system has about 10 gallons of nutrient solution total between the 3 x 5 gallon buckets. Humidity is pretty low in the room, around 34% even with a humidifier running. Temperature is around 75, water temperature is 69-71. I recently switched to 12x12 even though the plants are small, i was doing 18x6 before

This is my first attempt with PH perfect, i have several grows under my belt
I thought it would be simpler to use PH perfect w/ RO water and not have to worry with adjusting PH, adding cal/mag etc... the water looks perfectly clean, roots are nice and white, everything is perfect except the plants lower growth looks terrible! Almost wonder if it could be a pest problem.

I'm not sure what strain these seeds are, I had a plant hermie several grows ago and kept the seeds, this grow is from them. Is it possible the genetics are just bad? Seems unlikely. Thanks again in advance!

If you think it's a pest problem then take a very close look at the plants especially under the leaves. I don't think you have pests. I think you're PH is out of whack.

p.s. - Meant to say mixing each of the 3 parts @ 2ml/liter not 2ml/gallon. I've looked with the 20x magnifying glass i have and can't see any pests.

Definitely not a genetic issue.. Plants are not genetically just going to die.. Are you positive that you didn't accidentally mix you're nutrients wrong? It doesn't look like nitrogen as they are becoming necrotic rather than cholotic. The way they are drying and curling up looks almost like a P issue. Double check your pH, like @xtsho said.

so you have 3 buckets sharing 10 gallons? if so, I doubt if this is enough. your ppm looks a little low, your leaves look light green. are the roots down in the water? Is this really a dwc grow or more like aeroponics with roots suspended in air with periodic soaking? I'm confused on the grow style. try getting the roots deep in water/nute mix and see if the leaves will green up. consider raising the ppm too.

The pictures scream pH PROBLEM!!! Make sure your meter is correct and drop it to 5.8. See what happens. You can't be sloppy with pH in DWC.
http://www.ilovegrowingmarijuana.com/hydroponic-growing-schedule/

Sean Bass said:

I thought it would be simpler to use PH perfect w/ RO water and not have to worry with adjusting PH, adding cal/mag etc...

Click to expand...

Why would you think you can skip the Cal/Mag?
https://www.rollitup.org/t/do-you-use-ph-perfect-if-so-i-have-a-calmag-question.623044/

With the PH perfect line I am running, they specifically to not adjust the PH or add Cal/Mag. Supposedly the nutrients are chelated so that they are effective at a broader PH range, and if used with RO water as recommended nothing should need to be added.
This goes against everything i'm used to as well, but i'm just repeating the instructions/recommendations/what others who have used the product said.

I guess i'll try lowering the PH and see what happens, the plants are pretty much ruined anyway. Thanks for the help

Sean Bass said:

With the PH perfect line I am running, they specifically to not adjust the PH or add Cal/Mag. Supposedly the nutrients are chelated so that they are effective at a broader PH range, and if used with RO water as recommended nothing should need to be added.
This goes against everything i'm used to as well, but i'm just repeating the instructions/recommendations/what others who have used the product said.

I guess i'll try lowering the PH and see what happens, the plants are pretty much ruined anyway. Thanks for the help

Click to expand...

Have you tried it with tap water?

No, it says to use specifically with RO water, not to mention my tap water is over 400ppm.

Thanks for the attempts anyway.