You must keep that post in a file as you use it often in pointing out that its a guideline and not absolute science.
It's not some absolute one topic issue with nutrients.
You cannot finger every issue on nutrients.
Observations tell you otherwise, simple test etc.
Either that, or perhaps everyone else is lying and the person questioning thing sis the only person or a small group of me too's, while the rest of us are in some conspiratorial cabal.
That does not jive either.
If you compare other folk's tanks to yours, what may have worked for one person, will not always work for you. Maybe they messed up CO2, maybe they have more, less light than you, different plants, different starting point , filter, flow, current, % water change, poor test results.........
You do not know who to believe but if you keep failing, you try something else naturally..........
I hope so anyway.
Thing is, there are things you can rule out and know that it's causing the issue.
This will get you much farther ahead.
Not everyone is a good observationalist, not everyone is a good scaper right away either, a few are............so many will not hit a decent abalnce with light, cO2 and ferts.
But you cannot discuss ferts without addressing light and CO2.
I make clear mention of this in the articles I have written dating back to 1996.
Folks only read assume EI means weekly 50% water changes.
They do not read much else.
I think watching the plants is the best thing personally.
But you can rule out nutrients pretty easily, add non limiting amounts.
Then it's an issue of light and CO2.
Moderate to low light= > CO2 ought to be fairly easy to target and the only real thing to watch for.
Add Excel if you have algae while you dial in the CO2 good.
This should not be that mysterious.
I nag about nutrients. but CO2 and light equally.
Some suggest all I talk about is water changes, but I suggest non CO2 more than just about anyone that also uses CO2.........And variations in between.
It's rare, if ever you see me tell folks to add MORE light.
I ARRIVED at dosing via eyes, then went back and tested and measured.
Once I had mad pearling and healthy growth of a wide range of wimpy plants, then I knew I good reference to compare.
So then it's worth while to test and see what those good conditions are, rather than going in with an assumption from the start. If the dosing works at high light, then it will certainly work at low light as well as high and medium light. You might need to add more at lower light, but doing so should not harm or induce any algae, poor plant growth either.
Water changes just reset the tank, it does not mean you must do them either. Many fish only folks go longer time frames, as well as myself.
But if I wanna stay on top of things, or if there's an issue:
2-3x water changes a week, blackout maybe, Excel, pruning, cleaning, filter cleaning, dosing, then focus on CO2 and tweaking that, looking for any CO2 loss/changes etc, careful watching of fish etc. Reduce light if it's not down in the 2w/gal or less range.
There's no secret, this is the same old thing and has been for years.
Folks that hit things right, understand and get, some of us have more troubles for many reasons.
But it's not the methods of dosing that fail, it's us.
I've doubted many things, but then came back and realized that was not it later.
Then I move on to the next most likely culprit.
I think in person this is pretty much common sense, and you can look and see in person and quickly tell, on line, it's much harder to pinpoint things and help out.
Maybe I sound like a broken record, but these same issues have come up a dozen times or more in a dozen years on dozen boards.
So you get many of the same old issues for many, and you also get many of the same success % as well.