Tonight I'm more in the mood to "teach a man to fish" rather than "giving him a fish".
Well, I keep fish, but I hate eating them. But I like learning, which I hope is the analogy.
Plantex is Plantex CSM +B. However, you can use Flourish comprehensive instead if you already have it. They are both trace mixes.
I probably should mentioned how I started. I figured the Seachem liquids were easy, well known, and lots of information on dosing, so I started entirely with them. My intent was to work through the more expensive ones later and convert to dry. Potassium and Phosphorous were no brainers in terms of being easy.
But a side effect of doing this is that I have things growing nice and seem to have a good balance, so that I'm (rightly or wrongly) less looking for "how do I dose" than "how do I keep doing what I am doing with dry", which includes "maybe you shouldn't".
So feel free to also say "you are doing it wrong in the first place". Just in case it helps to know where I'm coming from.
If you're willing to do monthly water changes, you can still obtain non-limiting nutrient levels without much need for testing. Here is a post
that makes sense of a lot of this lingo.
Basically we want to keep our tanks within a range for each nutrient. We are dosing macros and micros. There are three macros, Nitrogen, potassium and phosphorus. The micros are everything else. Rather than worry about each individual micro nutrient we can dose one micro mix targeting iron. Most micro mixes are already balanced. That eliminates a lot of calculations. So basically we only need to worry about four things.
Here's where I get confused. I've encountered those calculators and descriptions (though not your specific very clear one) before. I get the principle, but not the mechanics, especially with regard to iron.
I can test it (Seachem Multitest Iron), but I've had wildly conflicting advice, even reading the Seachem responses on their forums. Fundamentally it seems to come down to "dose to maintain 0.1 ppm" and in the same breath "you probably can't detect iron as it is immediately absorbed".
I'm new to Aquariums but not new to English - How exactly do I "maintain" a 0.1 ppm level if it disappears before I can measure it? I had someone else in a different thread tell me by adding (example) 5ml to a 45G low tech tank daily I was severely over-dosing iron. So while I can use the calculators and know what each dose adds, I do not know where it goes, and I'm pretty unclear how to tell if I have enough since it can't be tested accurately.
Aside: I guess that dosing chelated solves this "cannot test" problem?
Phosphorous is easier - I'm working on getting that to 0.2, though in reading your note that's still low (right now it is "trace" at best).
Potassium is easy because while I can't test everyone tells me that it is very hard to over-dose.
dKH takes care of calcium, Nitrates are OK though in one tank I'm actually loosing and probably need to add more fish or think about dosing.
So you can see why I come down to iron.
Basically, all we need to do is balance dose size to water changes. That's where the dose size and weekly water change idea stems from. We can alter that. It simply takes a little common sense and basic knowledge.
Yeah, but this presumes either knowledge of uptake rate, or ability to test. And that's why Iron is so confusing -- right now I'd adding iron that I can't test for. The plants were yellow and growing slowly before I started dosing iron, they are healthy and happy with what I add. So in one sense that "test" is passed, but it is not quantitative.
Sorry... long winded answer. I'd appreciate any "how to fish" guidance, especially as to Seachem's "maintain" and "you can't detect it".