First time grower seeking advice

[Menequadon1]

Hi there, I’m on my first grow using a 2 x 4 AC Infinity smart tent kit that I bought earlier this year and growing two plants in soil (fox farms happy frog/ forest mix) running with seeds from Therealseedcompany. I have deep chunk and Afton 90 and they’ve been growing since about the end of March. Chunk is doing well and overall quite healthy but Afghan has been suffering from mistakes that I made when watering. I’ve been using distilled water, which I add Calmag to and pH balance to somewhere between 6.3 and 6.7 usually.

My main problem is that I’ve been using Google Gemini to give me advice and I’ve realized that that’s not always quite accurate (who’d have thought). It led me to use water that was not pH balanced and did not have any calmag, essentially ruining the soil in Afghan and creating a lockout situation, which I then corrected by balancing my water to the right pH, but still not using any Calmag.
Long story short, Afghan has lost a good amount of her foliage and is now pale green to yellow on most leaves with a great amount of empty space.

If anyone has recommendations on how to fix this and where to go from here, I would greatly appreciate it, as well as any general advice on how you water and how frequently you add nutrients, what pH you aim for usually, etc.
thanks in advance, and I will attach photos of where I am at right now. Afghan is the plant on the left and chunk is on the right.

 

[Ninjadogma]

Based on the overall yellow tone of the plant, it looks it's sitting in high EC, not starving. A couple deep waterings can put it back on track. Doesn't need more cal mag, needs to get past what's locking it up. So you've got a yellow tone and burnt tips and if you're not overfeeding then you're not putting enough volume of water through the soil. No need to get hung up on pH. There are some buffers in that mix to help prevent drift. If you're mixing nutes you want to check because they can significantly change the value. Other than that, just let the soil handle it. Those pH pens are notorious for being inaccurate and you start messing with it in soil where there's no problems, your gonna have problems. But if you have an EC pen, it wouldn't be a bad idea to collect some of the runoff after you are done watering to see where it's sitting. Don't collect at the beginning... Wait til you're done to look at it.

 

[Menequadon1]

Ok thanks for the response! So should i just flush it again with distilled water? And should I balance it to any certain pH? I have a pH pen that also can measure EC. I’ve been working with a feed water feed kind of schedule where every other watering I add nutrients. At this point, I feel like I could have flipped them to flower, but with all the issues I haven’t wanted to stress the plants out too much before I do that and they do have some room to grow still.
Also, I’ve been adding about 1.8 teaspoons of calmag to the water each time. Is that necessary every time I water?