Brown spots on leaves HELP please

Well the bigger patches just look like some Ph fluctuations but that first pic is a bit scary..hoping its just cal/mag issues from ph. otherwise you better flip some leaves over and scope em. and you say spreading fast, sounds and looks like spider mites. I'll hope its a calcium deficiency for you though.

Okay in the interest of helping others. If you know your plant is getting what is needs.. It's young so it's shouldn't need "huge" nutrient changes. Then you've got to learn towards pests or roots... If you don't see pests or eggs. Then Bacteria is most likely "fighting" with the plant in the root Zone. Bacteria that are harmful to plants will have a relationship that allows for both to live. The bacteria won't multiply fast enough to kill the plant but they will multiply fast enough to compete for the Precious resources used for functions of "life". In hydroponic situations using "root zone" cleaning products is almost essential. Products like UC roots or Hydroguard can keep your reservoir water clean and prevent this from happening before it happens.. You can use Hydrogen Peroxide as well to clean your system.. But this is generally not an end solution. The hydrogen peroxide kills Good stuff as well as bad stuff and also turns to water rather quickly so in 2-3 days your water is basically in the same state it was before and bacteria will be allowed to grow and thrive again. I hope this provides you with the information your looking for.

it is not calcium neither magnesium.that plant seems to be sensitive to ph fluctuations.try to keep it at 6.1 for a week and observe closely. 6.1 is a nice spot.

I currently am adding 9ml per gallon of calmend so idk how there would be a calcium or magnesium deficiency unless the oH was to low but I alow it to fluctuate between 5.8 and 6.3.

Okay because your getting a lot of conflicting information. Look at this https://www.growweedeasy.com/wp-content/uploads/2010/05/hydroponics-ph-chart-marijuana.jpg. You actually should just try running you ph a bit higher. Try to change your ph... a ph that changes between 5.5-6.5 every couple of days is what all strains/all plants Iv'e grown seem to love best.. I had a ultra violet og do something similar in my diary. Ignore the horrible pictures and go to week 3-4 you can see my plant looked similar.. Droopy.. overall kind of down.. This will likely fix your plant. The science is sound :)

try to avoid big ph fluctuations

To me it looks like pest marks, check under the leaves and see you haven't got any little buggers under there. If not then I'm guessing magnesium defeciency.

This a calcium deficiency. I've seen it quite a few times in a few of my grows so no the humidifier is not the cause. This is easy to fix though just add some Cal-Mag to your feeding regiment and things should start to turn around. Hopefully this was helpful and remember Happy Growing and Free your mind one puff at a time.

Hi there! Humidifiers don't do that in my humble opinion, although the accumulated droplets on the leaves can act as a magnifying glass and burn the leaves if a HID light is shining on it. I would rather check the roots, see if everything is going Well and check your ph. I have always been growing in soil so I might be wrong. Good luck buddy!