What nutrients do you have available to you right now?
All depends on what you have.
A simple 1-1-1 will fix everything.
Look at the NPK ratios on your bottles, look for one that is even, or has a little more N than PK.
This is the bottle you want to use, now most will say 1-2ML per liter, you want to use whatever they ask but cut in half.
So a 3L Pepsi bottle filled with 2ML would be fine, or even a little less.
Dilute it to 1/4th basically like you said.
The yellowing is from not being fed, but feeding the plant any amount of N will fix that issue quickly.
To give you an idea, my grow area is being recorded 24/7.
One of my plants had yellowing at the bottom, this was because I was actually flushing nutrients out of the container rather then letting them soak in. I was getting a reading of 2000PPM in runoff so I thought 1/4 nutrients than full strength would help sort out the high PPM, it only made things worse because I had flushed out so much nutrients, when I did another reading, the PPM was below 300. I added some 20-20-20 at full strength, and within 24 hours the yellow turned green (Even saw it in the timelapse of the recording, really cool shit.)
