Planted Tank Guru
Join Date: Nov 2009
Location: Missouri united states
Simply add both KNO3 and KH2PO4 or K2SO4 and potassium is covered with either.
I understand the reasoning behind wanting the fish,fish waste to make up lions share of nutrient's via el natural ,but this may not be doable as plant mass get's larger.
Different plants may very well have differing rates of uptake as well.
I also understand the fear of dosing inorganic salts by some for I was one of them in the beginning.
Learned fairly quickly that by giving plants a little of everything,that I spent less time trying to figure out this measurement or that ,or wondering as mentioned that as plant mass increased, do/would I need more?
I was also relieved to discover that the dry fertilzers I was adding had zero affect on fishes,shrimp and that algae became less and less of a problem.
If you are considering going with pressurized CO2 at some point ,then plants will demand much more than fish food and fish waste can provide .
Don't make things tougher than they need to be.
Put away test kit,add maybe 1/3 or 1/4 EI once a week or two for low tech and get on with growing plants and watching fishes.