Because the macros are only part of the solution, all the micros are required as well, along with the light, and the CO2, and they all absolutely, irrevocably must match/balance. Which is why that every time I go up to over ~2.5 W/gal, I burn out and drop back to lower light and slow growth. I will not devote the time and care/pruning/feeding needed to balance plant mass, light, and CO2 against fert supplements. I run slow, but algae limited. My plants are not show or competition, but I am not doing AGA tanks - I am not a plant collector ("How many species can you have in a 20 or 55?"), or a photo-ready aquascaper. A tank with 2-3 species or types of plants is my ideal, 4-5 my max, at six I start seeing the tank as too busy to be a background for fish - forgive me, but to me too un-natural. I grow fish tanks with plants, or planted fish tanks, not plant tanks. My tanks are for the fish, first, last, and always. And I have 2 dozen of the things - If I have a tank that require several hours per week of attention, I am not caring properly for other fish, so I do not go there often or for long. So I supplement only when I must (K regularly, N not infrequently, C pretty regularly, traces sporadically) and when I prune (not often enough) I overdo it and invariably have a period of detectable hair algae for several weeks (I do not learn certain lessons easily). Then things settle down again for several months and we repeat the process. But I do know the plants that I grow, and what they will do in my hands and with my erratic care - so I can deal with them. But details of my care are not going to generalize well to others. I do know my water in fine detail, but do not monitor nutrients closely - If I get off, the plants will tell me. If I over-feed or over-light (I always under-carbon supplement), the algae tells me. And I compensate from there, or ride it out when I know the cause as I usually do.
My tanks are all gravel-laterite or Flourite or Flourite-gravel, and I can handle those. My plants are some swords, more crypts, Anubias (mainly nana and near-nana cultivars), Val, and some Java moss, plus small numbers of Crinum and Apons. Anacharis or Val or Java Moss in the veggie filters. Most of them have been with me for years, some for decades, only a few at any time are "new" to me. I can't transfer their handling on the boards, because it is too tied to the way my tanks are run and operated.
So for general instructions on dosing, listen to Tom Barr or Len, they are much more mainstream than I am, and Tom has taught me a lot - including spurring me to try water column ferts, which took no more time to learn than the trial tanks needed to establish anyway. I just followed his suggestions. Once I had learned of course I dropped back to my erratic ways, but now I can work either way without fretting over it.
I think that not fretting is a basic requirement for me. I know that I can do high light fast grow high maintenence (read as: frequent attention and care) tanks, but I neither want or "need" to do them. My goals for my tanks tend to revolve around some sort of tests - filtration techniques, breeding, reaching or exceeding "wild" size, or how much longer a fish can and will live in captivity versus the wild. They are not short term, high upkeep, or even usually display. I only do 2-3 real displays, and those are the places I sometimes go for higher speed - but I do burn out on it as the payback to me is not enough. I want tanks I can sit in front off anytime and find somthing to watch that is diverting and relaxing, not somthing that is going to list for me the supplements it needs tomorrow and the pruning I need to do on Saturday. So my goals are not Dutch, nor even Amano (but some of his work is closer, more of his early work than the current style), and certainly not AGA. Those are fine, but not me. I am not a planted tank person; I am a fish tank person, with plants where possible.
