This is my wild guess based on your first post.
Wild guess...
Coco is causing some kinda lock. Was it conditioned and saturated with minerals?
But thats only a clue not the whole cause.
1/4 strength feed is not enough with coco that has no n-p-k in it. Nor any cal-mag-mn-or anything in the coco!
Your water should be fine you (assuming) checked it is 6.8. Might not be getting enough water. If the soil has been on the drier side consistently it will drain much sooner and much more than what its holding capacity would be if it was wet then dried to moist then watered wet again etc. Giving the observation that its running off already then thinking incorrectly that the water might wick upwards.
Heres the wild treatment. Soak the whole pot, large plastic tote. Deep enough to cover the soil. Till the plant stops floating, settles and sits for 30 minutes. This will flush and thoroughly wet the entire medium, including the possible dry pockets. Let it drain. Remember how much it weighs the next morning then give it a full strength feed, half of it now and the other half the following day. There should be great improvement after that. And can dial in what it needs after seeing its response. Get some dolomite lime too will help bunches.
Dont take my advice, wild guess wild treatment I could be wildly wrong. Just take the direction im giving to look for an answer you feel comfortable with.