I don't think that's quite right.

You cannot use KNO3 purely as your source of Kwithout using something like
KCl or K2SO4

It is not correct to say that there is 4x K compared to NO3. (I presume you
are using molecular mass)

If you dose KNO3 to obtain nitrates of, say, 10ppm, your K will be less than
10ppm. Now, I am sure this is fine for plants to grow, but your opening
statement says "Keep the NO3/K+/PO4 in good shape, 10ppm/10ppm/.5-1.0ppm"

To achieve your quoted ratio, you will need KCl or K2SO4


What source do you use for K+ ?
Thanks Tom.

KNO3, you can use K2SO4 if you want independent control of K+ without
affecting NO3/PO4. I also get a little K+ from KH2PO4, I do not need
to dose any K2SO4 since I get most of the K from KNO3 I need to
support good plant growth. Most folk's planted tanks are like this
unless they have a load of fish, high NO3 in their tap etc then adding
K2SO4 or KCl is added in place of the KNO3.

So in most cases, folks get enough K+ from the KNO3, roughly 4x the
amount of K relative to N. So there will always be an excess of K if
you have a moderate fish load, good plant growth, low NO3 in thr tap
water etc.