Compacted deep roots like in the pot you have are ideal conditions for root rot(Pythium) you just need one spore and its good night to all, deep pots like this are a great way to SQUEEZE out the air in the root zone(compaction) no air and much water makes rot, .. add a spore and again its very bad, if the light gets in thru PET translucent plastic, then you can also expect Algae, a long shot perhaps, but still a chance, I know as I struggled for a long time with this cause my trainer years ago always said cannabis likes a deep pot, I still agree but it has cost me several grows and a lot of un necessary money trying many pots, but air pots are the best and not very deep either.
see it as layers of saturation, the bottom layer too wet the top layer bone dry ...?
What's the reason for black over white? ...........the real reason is the plant hormone Epi.....(fuck can't remember the name in English) only works in the dark, and is the babe that makes root, as per 18/6 vs 24/0 , compare root development, and also used by cloners, esp. bubble cloners thats me, keep the cutting tip in the dark fed on ph neutral water annd air, and the "Epi".... grows the rootlet in about 10 days.............................no I need to find that "e" word ..lol