HELP! Seedling yellow and growth stopped, DWC

[zeek37]

Hi all

I am a first time grower using DWC. I used rockwool to germinate a seed, and transplanted to a net pot in a 5gal bucket after the first two ‘real’ leaves grew. Using a ‘space bucket, setup for lighting/ventilation on the single plant.

It’s been about a week since with little to no growth and the leaves are yellowing. I noticed the rockwool was quite wet so I lowered the water level and put some clay pebbles underneath it in the pot to stop it from wicking so much water up. Doesn’t seem to be improving anything. I have also added some tinfoil shielding to stop light penetrating through the clay pebbles into the water, not pictured.

Any advice?

Water:
pH 5.88 @ 18C, 120ppm

Had some nutes at 400ppm but flushed it a few days ago thinking that might be the issue. Currently just water. pH tends to trend upwards but I am monitoring/correcting twice daily.

Two stone bubblers running 24/7

Air:
Day 76F / 35-50%RH,
Night 68F / 30-40%RH

Lights:
2x 60W grow bulbs,
LED strip pulling about 60W​

 

[DW2]

Howdy zeek37, I do not generally go by the PPM method to gage the nutrient levels. I just go by the manufacturer's recommendations (GH line). Their levels (at the seedling stage) show an equivalent PPM level of 350-450 at seedling and 800-1050 at the early growth. I think tht the plant is starving for not only nutrients, but light as well. Some more details about your set up would be helpful as well (nutrients used, feeding schedule, etc.).
Good luck with your grow.