Plants not growing - cannot find out the reason

Hi Community!
I have an issue with my indoor farm with the plants in the white buckets. The plants are not growing at all, neither the roots, that are also getting ‘’darker’’. I tried everything, I made sure that all parameters were correct, they are still not growing, for more than 2 months. I talked to many ‘’experts’’ online, and they are all telling me the same thing, which is to double check all parameters and conditions, which I did multiple times. You can find the conditions/parameters detailed below.
The plants in the black buckets (Auto-flowering) are evolving in the exact same conditions as the plants in the white buckets. They are also similar strains, so there is nothing wrong with the strains. The pumps for each system are similar and working well (we clean the filters and pipes regularly). I am desperate as I isolated every parameter for plants in the white buckets, but still nothing changed.
I am looking for an expert who could assist me in finding the reason why my plants on the white buckets are not growing.

STABLE CONDITIONS:
EC: 900 PPM
Light Model: Mars Hydro & Spider Farmer
Light power: 320 - 500 PPFD
Air temperature: 28 Degrees Celsius
Water temperature: 21 Degrees Celsius
Fertilizer/ Nutrients: Flora
PH: 5.4 – 5.8
Strains #1: Apple N Banana
Strains #2: Marshmallow OG
Strains #3: Drying Dreamers
Strains #4: Grease Monkey

EQUIPMENT:

Mars Hydro LED:
Spider Farmer LED:
Industrial air-conditional:
Industrial Dehumidifier:
Industrial water chiller (1 system for 4 buckets):
Extraction system - IN
Extraction system – OUT – with carbon filter
Fans X2
Buckets (Both black and white buckets are totally opaque)

Photos available

Looks like root rot do they smell? If so toss the plant.

The conditions seems fine, they seem to have an infection at the root level. The color or the roots seems to suggest that. Another way to tell is the smell. It’s a very common problem in hydroponics and unfortunately there’s not much you can do to cure root rot, only to prevent it.
Always flush and clean your reservoirs very often to prevent root rot, a correct hygiene is the key. You also want to replace your white buckets with dark ones and seal all the holes, light leak feeds the algae which in turn feeds the bacteria that causes root rot.
Some of your least affected plants can be cured by pruning and cleaning the roots, and remove the worst infected ones, but it’s really hard to cure.

Thank you for your advices!

BTW, I am using water from my Dehumifier for hydro, as my tap water is at about 400EC. Is it ok to use water from Dehumifier? Distilled water is abusely expensive in my country… thanks!

Yes, dehumidifier water is basically the same as distilled, so you will need to add calmag.

As an aside, I see you are growing some Compound genetics. I am also growing one of theirs and it is growing really weirdly, almost stunted and basically a dwarf compared to the rest.

Not impressed with them so far, was also the only one to germinate out of 5.

Dehumidifier water is filled with bacteria and spores which are terrible for hydroponics. You can kill them by boiling the water and then let it cool down, but I would recommend investing in a reverse osmosis system, which is also expensive but not as much as distilled water.

Oh yeah? What about in soil? I ask because I have used many of dehumidifier watering and I even went as far as collecting rain water in a gallon jug straight out the drain pipe coming off my house I can see that being an issue in an open reservoir though but what about in soil?

The microbiome in the soil will probably outcompete anythink that might be growing in the nasty dehumidifier water, so I think it’s safe to use if you’re growing organic.

Ahh ok ok I see makes sense might even be good for the soil and your rizho huh

I’m nor sure if it will be good as dehumidifier water can cointain a lot or chemicals, heavy metals and microplastics depending on what air it’s sucking, but at least it won’t kill your plant if you’re growing organic.

Ah ok got ya

Thanks a lot!