Cal/Mag issues?

[Zooted]

Hi everyone. This is my first post on the forum and first grow. I've been reading for many months now and decided to start one plant in a dual DWC bucket set up (one for plant, other to allow more water in res), which is now at week 6 of veg. This grow has been much experimentation with the cannabis plant and with hydroponics overall. As for the plant, she seems to be having some calcium or magnesium related issues, possibly due to not properly adjusting the pH. Dead brown spots arose first on established leaves and yellowing of lower and mid level leaves came on later. Plant and root growth is stunted. Roots appear to be healthy and i have noticed some new white growth near the root tips. I am stuck with the liquid pH test kit and am trying to get my hands on an blue lab electronic meter (if my friend would text me back..) so I feel like I'm shooting in the dark with the pH. The color stays primarily at a nice yellow (~6.0 I'm guessing), which is what my nutrient solution typically buffers to. If it starts to get yellow/green, I usually add 15 drops pH down diluted in a few mLs of water to bump it back down. Is yellow too high of a pH? I want it to be close to 5.8 but can never know for sure. When I noticed the issue progressing (banded yellowing) I flushed with Flora Kleen for 2 hours and put the plant in a new nute mix at 1/4 strength GH 3 part (2.5 mL/gal) along with 5ml/gal of Cal/Mag. Res holds 6 gals. The ppm came out to 715, which seems a tad high to me. She has been in this mix for 2 days. My only other additive is a bit of Hydroguard to help combat high res temps. At first the leaves had brown spots (necrosis) and recently acquired the banded yellowing. Any thoughts will be helpful to me!

Grow Details:

Strain: Papaya (Nirvana) around 7" tall in veg
4x4 tent
dual 5 gal bucket dwc res (connected by uniseal) holding 6 gal of solution.
2 air pumps with four stones in plant bucket
Mars II 400 LED
GH flora 3-part + GH Cal/Mag
Temps: 73-77 F Avg: 75 F
Res water temp: ~74
Relative Humidity: 45%
pH: yellow ~6.0
ppm: ~715

 

[dansbuds]

I'd quit adding anything untill you get good meters to read your nute solution . it could just be that the PH is off & the plants aren't feeding properlly because of it . & you could be adding calmag where its not needed & build up to a toxic level . go back to just your base nutes untill you get the meters .

 

[Zooted]

I was starting to think along the same lines. I am using tap which starts out around 115 ppm. Stems are purple as well. I'll be glad once I get a better feel for feeding/pH adjustment.