Brown spots moving inwards from marijuana leaves

A question from a fellow grower:

Im new to indoor growing so here is my layout. I use 5 gallon aeration smart pots, fox farm happy frog soil, 1000w apollo mh/hps light, sunleaves Mexican & jamaican bat guano, r/o water, wiggle worm earthworm castings and I also have used Advanced nutrients micro grow & bloom ph perfect, blackstrap unsulphured molasses. The symptoms are brown spots starting from the outside edges of fan leaves and eventually covering entire leaf causing leaf to become dry & eventually die. No bugs in my grow & the problem started when flowering started. The plants are 2 autoflower candy kush both 45 days old. One is budding and doing fine but the afflicted plant has been stunted since it showed its white hairs

I know you answered a couple of these questions but more info would help. This is usually a nutrient deficiency or toxicity from the acidity or alkalinity of your soil (PH) or from nutrient concentrations being too high or too low. I’m thinking most likely a phosphorous deficiency or maybe a toxicity from PH making something too available or from something too concentrated in the feeding regimen or it has built up in the soil.
Let’s get you started with a support ticket, answer all the relevant questions and we might be able to get an idea of what is going on.
ILGM Support Tickett
What is the strain?
Indoor or Outdoor?
Size of space?
Soil or Hydro? Medium used?
Type of nutrients used? NPK? EC/TDS/PPM/Nutrient concentration levels?
Humidity %?
Light system/watts/lumens/flux/par?
Vegetative Growth season or Bloom/Flower season? Number “weeks/days” from start of veg growth or into flowering?

hey i have some candy crush which were suppose to be feminized but the where regs instead so i got alot of males…did not get them from u thou so u did not screw up a order or anything but…
having the same weird problem with some of my plants,they are getting the exact same problem with the leaves getting brown spots just like in those pics and i cant seem to nail down what the heck is wrong,got any suggestions besides a good rinsing? i went to straight water except once a week feeding, i was doing a general maint with nutrients but thought maybe they are getting to much…just lost on this and need some help to get away from this problem. some have like colored new growth on the tops and lush green just below is that normal, it really doesn’t seem like it is.
i have kept my ph levels between 5.5 - 6.5 water and dirt both,i am using t5s for flowering and 1000 hps for the bloom cycle,also am using dyna grow brand, cal mag and and there kln rooting stuff and so on…should i switch to maybe some thing else or is it even have anything to do with it? also not all plants are affected most are just lush green babes just the way they should be, please give me some guidance, on the brown spot syndrome as i call it. also i grow with coco fiber dirt type stuff pretty great stuff.

Sounds like a nutrient lock-out, or possibly toxicity, likely due to a pH imbalance. How are you measuring the pH of your soil and water?

The pictures above, that is very likely what is going on, a pH nutrient lock-out. Most likely a phosphorous, potassium or zinc deficiency, or maybe all of them and more, again very likely pH related.

I’m getting Them brown spots too. What did you do about them

Beginner: I’m also getting those brown spots starting at the bottom of my fan leaves… what could be the problem