Yeah i wouldnt expect it to be getting worse if thats what youre doing. Dont need much run off, 20% or so is good. Just keeps the salts from building up which in turn messes with the ph.
No2 on your list is only a soil growers thing too. Coco is hydroponics, the clue is in the title. "Hydro" meaning water. Otherwise it would be called dryponics lol. If you let coco dry out the nutrient level in the pot rises.
No1 isnt really accurate iether cos too strong a dose in veg doesnt burn them it gives them N tox which is dark leaves, all clawed down and stunted growth. Its well in effect before you notice it too so not always a quick fix.
Sorry to correct you but coco and soil are exact opposite media in terms of everything. Different causes, symptoms, side effects and fixes for pretty much anything you can think of.
This is my 4th Coco Grow and i know how to handle it! I never dealing with problems bacause i read a lot what Coco needs and the watering every day is the kye but runoff is no needed when you give the Plant what she need she eat the EC in vege but flower she don't need much and Salt build up quick that's what's going on on her. I have a 2 plant and she looks great without burn ore deficiency.
What i need to now is the question? Is my EC 1.0 I Feeding with to High??? I can't watering with 20% runoff...... The EC is 1.3 runoff so why worry?