I raised and bred discus several years using EI.
This client of mine uses EI:
I'll let you decide.
Feeding is much more the issue, plants will actively remove NH4 directly.
NH4 and food waste are why do lots of water changes, however, if you wish, doing 2x a week 50WC's and dosing after is fine as well. You will just have less build up of nutrients and more stable ranges.
Water changes for non planted tanks and the build up of NO3 is not the same as KNO3 dosing. KNO3 does not start out as NH4 and high bioloading, it starts out as a relatively non toxic NO3. NH4 is 200-13000X more toxic than NO3.
So to add enough N for plants, KNO3 is much less stressful than simply adding progressively more fish(which also depletes O2 as well) that adds NH4 first and later is oxidized into NO3 via bacteria(which also uses up even more O2 for every N atom).
Not good.
Plants will use up most of the NH4 in a well balanced plant tank, but if you add too many fish, feed too much etc, then things can become a problem, this is due to low O2 and higher NH4 than the plants can use per unit time.
Lower light tanks, without CO2 etc can get all the N from fish waste, however, in high light CO2 enriched systems, we need to add N either to the water column or the sediment, or ideally, both locations and in the NO3 form.
Regards,
Tom Barr