overall is definitely high, but that doesn't mean everything is high. Symptoms are not discrete and when dealing with at least one potential toxicity it can make things look wonky for diagnosis.
Dial back, but if that chlorosis continues, something might be low, too.
individual concentrations and ratios are just as important as overall concentration. Promix BX has a very light charge to start, so it's a soilless context where you need to provide 100% of everything in a proper balance. There's more than on eway to skin that cat, but i'll type out a balance that has worked well for 7 years and rarely meets a plant that doesn't grow healthy deep into flower... which is all you have control over, anyway. the rest is just genetics playing out.
Also, EC is important for it's own reasons, but is a very poor measurement when converted to concentration. There are 3-4 different conversion factors that have nothign to do with anything important and 100% about the brand of equipment you bought... could give you a 40% different value for PPM when converted... that should explain enough. It's much better to understand concentrations provided by calculating ppm from gauranteed analysis labels. "Hydrobuddy" is an open source, free app that you can use for various platforms.
Vege - mature plants
PPM
N 120-130
P 40-60
K 180-200
Ca 100+
Mg 75-80
S 100ish
This is a fairly low and very safe starting point. From this you can easily observe and make minor tweaks to balance out with your environmental factors - light, co2, temp, rh. Even with this lower concentration i have to dial back a bit about 30-40 days into a grow. I drop to 90-100ppm N but keep the other things roughly the same. Then in flower N drops even more.
Flower remains a very similar ratio except for N is a smaller portion of the total than before. You'll probably be fine with 500-600 ppm - calculated not converted with some whimsical factor from EC. The nutes you use for soilless/hydro can be trusted. "gauranteed analysis" is a gauranteed minimum but when you deal with ingredients like ammonium nitrate, calcium nitrate, MKP, epsom etc.. it's not messy like soil fertilizers. The numbers can be trusted and expect them to be accurate. Molecular formulas dictate proportions of various elements and that cannot deviate or else it would not be magnesium sulfate hydroheptate or whatever it is, lol. Calculating ppms from such ingredients is very precise.
you could skip ppm calculation and calclulate weighted average percent of mass from the labels based on overal dose, too. This would be exactly the same thing, but look a bit different. I think ppms are more intuitive to work with, but the proportions would be the same, therefore the same information gleaned.
Trakcing this stuff over time will help you tweak that formula to consistently avoid 95-99% of problems.
proper irrigation habits for soilless is incredibly important. Some people are incredulous and those are the ones that fuck up.
1) fully saturate with a minimum 10% runoff. Always fertilize (barring a need to dilute rootzone due to a previous feeding mistake)
2) wait for appropriate dryback and repeat.
The amount of time between can be a greay area, butif you trigger an irrigation at the same loss of weight or same depth of drying up top, it will require a very similar volume each time. Do not choose a volume to give. You give what it takes to accomplish the task properly. Everything is observe and react as opposed to whimsical top-down choices. Don't think. See and react. That takes the guesswork out of it. Don't try to do unique things in regard to irrigating... these are well-established general practices for soilless growing regardless of species.