Browning/yellowing areas on bottom leaves

[GrowerNewbie]

Hi! I have posted here a few times as I am very new at growing.

I have some plants that have brownish/yellow spots on the bottom leaves of my plants. I am wondering what it could be and if it’s a fungus? I checked under the leaves and no mites.

I have posted a bunch of pictures to hopefully give a good idea of what’s going on. Do I need to remove the leaves that are affected? I’ve never removed leaves before so would I just take shears and cut at a 45 degree angle close to the plant stem to remove the leaves?

Thank you so much for any help and advice you can offer!

 

[Ghosttrainx]

HHey just flush 10 litres through the pot read the run off there just abit to strong nutes build up just low your nutes for a week leave them on its find or the tip will burn instead of leaf leave leaf on till it's at good stage to do it in one big shot less stress and grows quicker as it has a good root system to coup if u pluck them through growing here and there it will slow them down alot and not grow good

 

[Ghosttrainx]

See in coco u put the nutes in if soil there can be all types of nutes in there so hard to feed it right and it's breaks down making more elements in soil