Yes you can, does the vinegar first, then add the nutrient if that’s your plan.
Just to see first I’d go vinegar and water without any nutes. Preferably you’d be alternating. 1:500/water (water only days) then nutes another. Vinegar can be quite powerful so I’d only use it for means of making corrections.
In all honesty I’ve no clue about how organic soil and ppm works together. What I do know is if you alter the pH it can kill the benificial microbes within the soil. I know you need to feed the microbes and not the plant in organics but that’s the height of my knowledge
Big trick here is not to do everything at once. We all have that tendency when we care about our plants to want to do everything to fix them. But throwing too many things at them can cause other problems and also make it harder to really know what was wrong. First thing, you PH is too high, bring it down and try to keep it at 6.5, watch the new growth and see if it helps.
The kelp is good but remember too much kelp is know to stunt growth so don’t go crazy. You will see a faster result with a foliage spray but read the product dosage and application instructions and follow them.
The best thing you can do in my opinion is do one thing and watch very closely to see results. This way you will know both the problem and proper response, next time it will be no problem 
Edit - also don’t stress, your plants look good and this is a super minor problem you can easily correct 
Do you have a picture of the whole plant?
I’d water/feed at 6.3 to 6.5ph, and maybe a little more water each time. Based on the pictures I see so far, they might just need more even/spread water due to the size of the plant. Looks the the outer edges of the pot are dry.The whole root system might not be getting access to the water/feed so it’s not taking in enough food as well as the pH being a tad high
I think targeting a 6.5 pH should be part of your routine.
Plants do like consitency…
Nutrients have no use if the pH is not between 6-7, use that chart… above below they have no impact.
Mix the nutes, as you see fit.
A Balanced pH wins
You got it bro👍🏻
Thank you man!
Btw tag me whenever you feel like it bud.
Edited
Paws
That was a total 360 buddy 
Sometimes people just remember a name they have seen help people out. It’s a good thing your name was mentioned. Obviously something you did or said stuck with him.
Sometimes we need that person/grower we follow to the letter until we find our feet. Mine was @ReikoX. That man guided me through a lot when it comes to growing.
My mistake. I’ll be around @seeds2weeds , @Esrgood4u thanks for pointing that out.
Its all good man last thing i wanna do is be annoying lol.
I agree with this advice. I keep an elevated inner ring of soil that stays more dry. And, I water more to the outside of pot and deeper (not consistently waterlogged that’s too much). But, enough that encourages the roots to dive deep, rather than stay at the surface looking for water. I also alternate in w bottom fed watering once the plants get a little bigger. I aim to give enough water to last 2-3days
Thanks man my first act to try and correct things were to ph water to 6.5 and water entire pot until run off. Im going to monitor new growth.
Hey, you weren’t. I was rude. My mistake. Now let’s grow some green 
Its all good brother 
Awesome. Bad first impression. Like I said continue tagging me, I’ll help out.
Do you have more info on this molasses? How much do you recommend mixing to 1gallon to start?
Molasses is great just don’t over do it in a 5 gallon bucket I use 1 tablespoons total too much can be detrimental
Do you plan on making a compost tea ?
Molasses is awesome during flower and very beneficial to soil microbial organisms
I was thinking of adding some to some oh water if the yellow lines between the leaf veins dont clear up after soaking the pot throughly. I dont know much about teas and i hand water but im willing to learn anything
Also there is purple leaf stems which i would assume is mag deficiency as well?