Why do I have weird spots on my week 5 flowering chemdawg SWC?

[BassBuds]

Hey, so I'm seeing these weird spots on some of my leaves. They are dark in the center, with a lighter ring around them. I'm in week 4 flowering (SWC). Note, my plants have gotten very close to the light (sealed 400w hps) because they are in a bloombox so I only have ~3.5 feet of vertical space. I've been tying down the plants with zip ties to try to keep them far enough away, but it's a losing battle. Anyone have any idea what the spots are? This is my first grow, so I'm worried about having serious pest problems so close to harvest. Keep in mind, these spots are only on a handful of leaves, and only on the ones closest to the light. The spots are particularly noticeable when looking through them at the light.
Full grow log

https://www.420magazine.com/forums/journals-in-progress/299638-secondhand-bloombox-first-grow.html

Any ideas? Do I need to worry?

[fozzy]

let us see a pic of the whole plant. what is your PH?

[BassBuds]

I ph daily to between 5.5-6 (depending on which way it tends to be drifting. If it tends to be drifting down, I'll ph to 6, if it tends to ph up, I'll ph to 5.5). When I check it, it is usually 4.7 or so lowest, 6.3 or so highest.

Pics of the plant

[alltatup]

Yeah BB, you hit some of the nails right on the head, but it was a good starter piece of machinery for me, knowing absolutely nothing about growing 2 years ago, and I had a little inheritance money to spare. I read reviews and made comparisons, and the Roomie seemed right for me. It's a single chamber and grows 4 plants at a time. Yes, I always start from seed. What I really do like about it is its stealth and small size. But hell, I had no idea that a carbon filter cost $150 to replace!!!! Shiiiiiiiiiiiiit!! I was kind of wondering if I could take the filter apart and put in new charcoal... was gonna look into that. I don't know about the pin connecters.

[BassBuds]

You can take it apart... Or you can do what I did... Buy a 4" carbon filter for around $50 on Amazon and just use ducting to connect the two. The one I got is also reversible...Meaning you can move the flange to the opposite side so it uses the carbon from the other side.(I hope that makes sense...It's early)

[alltatup]

That's what's up, Buds!!! Cannabis cultivators are ingenious!

[NebulaHaze]

Overall your plants look great!

Do the spots look like these? This is a Calcium deficiency:




If so you may want to get a Cal-Mag supplement like CaliMagic or Sensi Cal-Mag Xtra. Calcium deficiencies can happen to anyone (cannabis is a Calcium loving plant) but they are most common when you have soft or low PPM water, or otherwise don't naturally have much Calcium in the water.

But honestly your plants look beautiful, and developing very nicely!

[BassBuds]

NebulaHaze I'm already using CalMag+ 3-5ml/gallon. After doing some research, I think it is likely a slight calcium deficiency caused by a PH lockout. My PH has been drifting down this week. I read that calcium is best absorbed at 6.2PH. So as of today, I'm going to try to try ph'ing to 6. I also added a gallon of water with some Great White and CalMag+. Thanks for the kind words on my plants.

[NebulaHaze]

It sounds like you are already on top of it!