Good Morning Phenoman,
I will probably catch flak over the next few lines, but follow my logic if you will...and please take my words with a grain of salt and remember this is but one man's perspective; mine.
Don't over think your pH...look at the last picture you posted. There is nothing wrong with that girl. Ok, I can see some slight leaf tip burn...this isn't unusual, especially as this strain dips further into its flowering and it begins to rely on less and less Nitrogen. Remember, you're growing in soil...if you were in a Coco system, or DWC or some other hydro process, you'd have to monitor pH, why?...because the only nutrients your plant can get come straight from the water you're putting in and, if the water isn't at a pH that allows all of the nutrients to be available to the plant, you'll get a lock out, a deficiency or an issue. However, you're growing in soil, and soil does not behave in the same manner, nor do the roots in soil react the same as roots in a hydro system. The soil is your buffer, your bridge if you will, connecting your nutrients, which lie in the soil, to the plant. It appears, though I have no experience with your soil brand, that you have a good starting soil, so unless it started out extremely acidic or basic, which I highly doubt being lots of people are using it with good results, I wouldn't sweat it. Furthermore, in terms of soil, you're growing this plant much like it would grow in nature...in the dirt. Stop and think for a moment; when it rains, does the rain come down in such amounts that it causes 'run off' from the top of the roots to the bottom, for every plant growing in the ground; no. In fact, where heavy rains and run off are observed in nature, and in farming for that matter, what you get is barren, washed out land...not a growing jungle. Every time you water your soil to run off, you're leaching out the nutrients in that soil and if you're chasing a pH number in that run off, you're essentially chasing your tail and in the process goofing up your girls.
In my situation, I use soil, premixed and amended by me with granular, natural organic fertilizers (liquid nutes, which are essentially dissolved 'salts' can bind up your soil and accumulate to levels that harm your plant/s and force you to leach your medium, which is not something you want) prior to putting the seedling in the pot. I don't pre 'cook' the soil, nor do I worry about its pH (this does assume you're working with a quality soil). I then take regular ol' water from the hose / tap and water as needed just to the point of saturating the pot without any considerable run off. That's it...the nutrients in the soil will break down over time, feeding the plant throughout its entire life cycle, the plant will use the nutrients as it needs them (plants are a lot smarter than we sometimes give them credit for) and in the process the soil will be your pH pen, your calibration solution, your pH up or down, etc...in essence you set it and forget it.
So what does this all mean...nothing really, except that like everyone, I have an opinion too...haha. Seriously though, the proof is in your picture...You're doing fine! Don't over think the process...let your girls have their way in your soil, sit down and observe them on a daily basis, note how they look in an over all general sense (and they look damn good to me) and listen to what they have to say to you (c'mon now, we all know they can talk...haha). You're well on your way to Indica heaven my friend.
Have an awesome day!
(granted a proper mix and I shouldn't be messing anything up).
