I'll be the first one to admit I am still a novice when it comes to running a planted tank, but I was just concerned with providing the correct dosing schedual for my tank.
I have recently converted over to a better setup,and will probably start dosing using the EI method, what concerns me is when I reset my tank with a water exchange.
Should I be adding Kno3 right after the exchange since there is always going to be plenty of Po4 in the tank? I just dont want to throw off the balance of my tank and have problems arise.
As mentioned already, you may not need to add KH2PO4(assuming the PO4 is present).
Just do the other stuff and take that off the list of dosing.
Then focus well on CO2.
CO2 causes far more trouble to dosing routines than the dosing itself, which is rather easy and straight forward.
Whether the ratio is 10:1 NO3:PO4 or 5:1, does not matter.
If and only if the levels are non limiting to plant growth.
You generally try to focus on getting less waste and tweaking things to that end more, but keeping things into the non limiting range is generally wise.
Then you can focus on CO2.
If you want more wiggle room, less light is the best thing to "limit".
Slows growth down without having to limit or test CO2/nutrients.
And also places less demand on CO2/nutrients, so if you want to use less, it provides the best solution, also if you like to prune less, do less work, and do not mind slowed growth rates, light is the best variable to change since it drives everything else.
Some folks never understand that and assume a lot about nutrients/CO2, then never test or measure light(or CO2 well for that matter as it interacts with light intensity).
Many think more = better when it comes to light.
I've been telling folks that's not the case for decades now.
The rational is really simple and founded in the very core of Plant Science.