COCO COIR Help! Rust spots on biggest plant.

[Hmndtyphn]

Hey all, this is my first grow, im on about week 4 but I did stunt them out a few weeks from not knowing to treat the coco coir before transplant. They have all seemed to heal well, and began growing rapidly again, except one which is literally double in size to the others. That big plants leafs are currently showing Rust spots on most of the older growth and it happened rather quickly. None of the others are showing any signs of issue or deficiency expect one on the opposite side whose tips began yellowing slightly (that one is one of the smallest, thinking toxicity and just going to water with tap to clean the medium)

My big issue is the big girl with the rust spots. As everything else is green and beautiful, she's a bit dark green and showing rust spots. I'm thinking deficiency and will water again tomorrow morning, any thoughts on the issue???

Tent- 4x4x6
lights-
Right side: Mars hydro ts 1000w
Left side: HLG 100 V2
growing in coco/perilite mix
2 gal smart pots
temps range from 83-75
R/h 65-50
running inline fan to pull from tent and 2 Vivosun 6"

Seeds are photo from a friend's local dispensary.
2x The one
4x breakout

Nutes:
full tsp of calimagic per gallon
half full dose of flora/ half does of bloom
ph fluctuates between 6.2-5.7
typically watering every other day until 10% runoff

[Mr.furley]

You're letting the Ph swing to low, stay between 6.0 and 6.3.

you should be giving 5ml of cal Mal and by this age full nutrient.

[Hmndtyphn]

I'm also using distilled water, and I'm thinking of switching to spring or tap water. And thank you! I'll keep the ph in range, and start giving full doses. Would a double dose of Calimagic for that plant be a bad idea currently? Should I just correct ph, and fully dose w/ calimagic, flora, and bloom? (I'm not using the Gro, just because its my first time and I was nervous of burning them out with nutrients.)

[Mr.furley]

I would suggest watering at 6.3 the next 2 time.

Instead of giving double the calcium give them twice the water with 5ml each gallon, the extra runoff will reset you medium.

Add half strength grow and see what it does, you shouldn't need bloom till the second week of flowering.

[Hmndtyphn]

The Girls are looking MUCH better and are drinking more and more! Thanks so much for the help.

[Mr.furley]

That's great news, they look real healthy.

Thank for updating and you are very welcome.