Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
You can adjust the dosing to suit the tank.
If you have not been dosing any nitrogen, what is the NO3 doing? This is testing NO3 from fish food.
Fish food supplies reasonable amounts of N, P and most traces.
Fish food is low in C, K, Fe, Ca and Mg.
Water with GH over about 3 German degrees of hardness usually supplies enough Ca and Mg, though you could supplement with some GH booster if you want.
For a low tech tank with a reasonable fish load, the NO3 may hover or climb slowly between water changes, suggesting the plants also have enough P and most traces.
Dose K, Fe and C (Excel is fine for Vals, just do not dose the loading dose).
If the plants are removing pretty much all the NO3, then dose some N, P and traces, but you might go with a very low dose. Just enough to keep the NO3 about 10-20ppm.