Yellow dying leaves, brown circle spots, keeps happening

I grow in coco/perlite.
Ph to 5.8-6.0
Maxibloom 5-7grams per gallon
Epsom salt 1gram per gallon
Lights are all Kingbrite 240w around 18-20" away

I been getting these yellow leafs and brown circle spots and they die. Usually in the lower area of the plants and late flower, week 5.. I feel like it's some type of mold getting spread, I've checked with my jewel loupe and I can see black. I just pull em off when they get really bad, not sure what's going on. I did have thrips but took care of em with Captain Jack's every other week. I pH my pen monthly with the quick cal solution from Hanna. I also do mysquito bits twice a month because I had a bad gnat issue, but it's been eliminated. Also to know, it's only on some plants..
the ones on it at Big Detroit Energy and slurricanes. My kushmints don't have any issues.

That water circle and the dry coco makes me think watering practices need work. Are you watering till runoff every time? Maxibloom should be good, doesn’t look like pests, would guess ph, lockout due to lack of watering/drainage. What’s your water source? What ec does 5g of maxi give you?

Magnesium deficiency

Cal mag foliar spray.

TBH

J232 said:

That water circle and the dry coco makes me think watering practices need work. Are you watering till runoff every time? Maxibloom should be good, doesn’t look like pests, would guess ph, lockout due to lack of watering/drainage. What’s your water source? What ec does 5g of maxi give you?

Click to expand...

I been trying to water once a day because its 3 gallon coco, its tap water. I dont measure EC :\ .. I usually do water until runoff but i wait 2 days after i water because I literally am so busy with work. Do you think I need to setup a automatic irrigation?

*edit*
before I had plants in 6"x6" and i watered everyday and soaked them, it was so tiring.. lol

Coco should be completely saturated at all times.
Feed daily to substantial run off.
Never let it dry.
Never use plain water.

If you don't have the time for coco, and you find the daily feeding tiring.........do soil next time.