Chlorosis on first true leaves

Hello guys,
 
I have been lurking constantly this forum to learn from you all but recently my own first habanero peppers are presenting this pale green-yellow-ish color in their first true leaves. They are being grown in polyurethane cubes.
 
These are the conditions of my plants:
 
Location: Northwest Mexico
Temperatures: 77° F- 104°F
Humidity: 30% - 80% 
 
They are growing in a plastic cointaner with these dimensions: D: 15'', W: 16.5'', L: 27.5'', which filters some of the light and gives protection from aphids, OTOH, it retains humidity, so I have to constantly be checking with an hygrometer and change air constantly.
 
The habaneros are receiving indirect sunlight (13 sunlight hours) in a range of 1,500 lux to 7,000 lux (some of them receive 30,000 lux for around 40 minutes per day). After sunlight, they receive 4-5 hours of artificial light of 6,000 to 8,000 lux.
 
They are being feed with an hydro solution specially designed in Yucatán, Mexico, for habaneros, with a EC of around 360 ppm and pH of 5.7. Some of them are receiving this same solution with some coffee diluted, which raises EC to around 630 ppm. Anyway, I do not discard this might be a nutrient problem.
 
Last friday I sprayed them with cinnamon tea for fungal protection.
 
Pics in the following link:
 
https://photos.app.goo.gl/BnTRN8j4Ek8KRrGs6
 
Thank you for your time!

They look very leggy so there is something going on with the lighting. Not sure if thats the cause for the leaf color but you need to either put the lights closer or give them more time under it.

Edmick said:

They look very leggy so there is something going on with the lighting. Not sure if thats the cause for the leaf color but you need to either put the lights closer or give them more time under it.

Click to expand...

 
Thanks for the response, Edmick. They were limited at first with light when they sprouted, which was my noobie mistake (one of them, at least!). Since then, they have responded well to light and some of those pictured are starting to get stems larger.  I'm currently testing one of the plants with the artificial light condition I said in the OP for 18 hours to look for (if) any improvement in that regard.

give em a week they'll probably balance out. Mine do that from time to time