Actually no, it's rather easy to determine the nutrient levels and
maintain them in one simple step.

No chem lesson at all, you can make cereal right?
Add enough cereal to fill the bowl, add 2 cups of milk, 2 teaspoons of
sugar etc.

Or I can say add 250 grams of endospermous carbohydrates and 9.5 grams
of sucrose to 450mls of bovine protein mammary milk.

In a nut shell, you do large weekly water changes(say 50%) each week to
prevent anything from building up and and dose 2-4x a week to prevent
anything from running out.
the names can be whatever you want them to be, but ultimately all you
are doing is adding Nitrate, PO4 , K+ (the NPK numbers of bags of
fertilizer) and traces.

Farmer do this without chem lessons all the time.

In this manner you provide a stable range of all the nutrients cheaply,
easily and without using a test kit except for CO2(KH/pH).

An example routine for a 20 gal tank with high light:

50% water change

Add: 1/4 teaspoon of KNO3
1/16 or a smidge of KH2PO4
If GH is lower than 3-5 out of the tap, Add SeaChem Equlibrium(1/4
teaspoon)

Next day add 5 ml of trace

wait one day, add the KNO3/KH2PO4 again, next day add the trace again

Add the KNO3/KH2PO4
Trace again the next day

Water change: repeat ad nauseum.

Dosing 1/4 teaspoon of powered KNO3 = 1.67 grams according to a lab
scale with 10 levels averages.

This added to 20 gal= 10-11ppm of NO3. Error is about 1ppm of NO3.

Name one hobby kit that can be that accurate?

We dose excess nutrients in all cases, nothign wrong with that as long
as we don't get too far off base and the water changes prevent folks
from lousing it up.

You can guessimate and use the plants as the indicator as you become
more skilled and dose less or go longer without water changes.

Again, no test kit is needed.

As long as you keep up on dosing and water changes, this is a very
simple method and no hassle if you put an automatic water changer on
your tank, python style water changer etc or hard plumb a drain/refill.

KH2PO4, KNO3 are very cheap, SeaChem Eq is relatively cheap as well for
the once a week dosing. Traces are not too bad at this amount.

Regards,
Tom Barr