First, it's slow-moving, it's relegated to bottom.. .most of the plant looks fine. it's good you are worried, but adjust it to scale of the problem. you should not feel overly anxious about this. based on some tidbits from diary, may even be caused in part by the irrigation habits.
so, it's limted and at bottom of plant -- that's a mobile nutrient and helps us further diagnose the cause. Someties plants shed lowe leaves, too... so if it never ramps up or spreads, i'd not wory about it too much. but does lean toward k-tox of teh various options. but, you ratios aren't bad at 2-1.5-4
130 N
50
P
200 K
are my NpK ppm. bcause of different densities, these ratios are a bit different. i don't know their npk versions cause npk values aren't apples to apples and i don't bother with them.
1.6-1-4 would be good for ppm... npk label values are different animal.
(Ca 100+ Mg 80+ S 100+ -- these will vary more based on water used) If/when you do the math on the K you added in total, if it is well over 200, it's a prime suspect at that point, assuming the soil has some too... (some tranlating -- i speak from asoilles perspectve.. you may feed highe, but if every 2nd irrigation, it shouldn't be more than double -- over time it still has to match the same plant's metabolism regardless of soil or soilless... can't force feed plants like foie gras)
you are in soil.. so if you feed every 2nd or third day, this will be higher, but you'd want to add the same mass of each molecule per week or per month etc (relative to how i explained the ramp u for soil context), so it is similar, still. you could use similar amounts in a daily feed once the plant has sapped what comes with the soil to start... until then it's a balancing act requiring familiarity with the soil's components.
a 10-15% runoff when you have fully ramped up your feed will maintain soil EC -- you basically treat it like a soilles grow once those soil amendments are used up.
check out what others using nsame products do... do the math using the online calculator.. you've got the tools and some ballpark ideas... start fertilizing again.
--------------- some bits from readng diary and more
(until now no water flowed into the saucer) -- even in soil, you definitely want "some" runoff... unliles soilless, excess runoff is just leeching anything your soil initially came amended with, so less is more in this context... but you still want some to ensure entire pot gets wet. re-occuringn dry pockets are a potential cause for nute buidup... doesn't guarantee it occus, but creates the opportunity for it to do so.
You have soil, so you have to ramp up your dose over time. i've never used that product, so i have no familiarity of how hot it is, etc... search diaries using those products with soil and look over the healthy looking plants and how they progressed.
expect some deviations in your garden, but a good ballpark to start.
if you feed every time later on, you'll max out at 1.2-1.5 ec as stated before. (600-750ppm). Total ppm is only part of the picture. the ratios of npk et al are important too. you ratios don't look far off but i can't do the math for ppm in my head. you can do that using a manic botanix ppm calculator.
too many unknowns with soil to give you a direct answer, and anyone that does is lying to themselves and giving bad info even if it coincidentally works. learn cause and effect to more effectively exptrapolate on you own over time.