My tank at home has EI dosing and CRS, they look and do fine.
So has Rain-
There's no new evidence that suggest I or she is incorrect about it, nor that the dosing needs to be very critical careful within typical EI dosing routines.
On the other hand, I would have to rule out every other possible factor to show that NO3 is killing them. Which is a much taller order and much more difficult.
Rather than proving that, I assume that a certain level should kill them, then add it. If it does not kill them or harm them over time, then I can assume that the cause is something other than NO3 for death, because when I did that and knew I added 20-30ppm NO3, I had no deaths, then I have done this repeatedly for many weeks, as have others...
So I have plenty of replicated time blocks, as do other folks.
The likelyhood I and they are wrong is extremely small.
These are reasonable logical assumptions that safely help uncover what is or is not hurting my critters, plants, algae etc.
It has nothing to do with belief, it has more to do with logic, testing and asking a good question I can answer by dosing KNO3. Folks that do not even keep any plants or dose any KNO3 at all also kill fish and shrimp.
So there is no control there and no control in the test.
If you can do it without killing them in both cases, then the tank itself acts like a control to some degree.
You are growing the plants, shrimp etc the "right way".
When you add something, they appear not to be effected at all.
Like adding PO4 to a well run planted tank= no algae.
You need no control because the reference is a well run tank to begin with where algae is not present.
If you chose a a poorly run tank with algae, added PO4, you'd likely get more algae and conclude that excess PO4 = more algae.
Obviously that's not a good assumption or a fair conclusion, whereas for the well run reference tank, it is.
Ideally you'd have separate control tanks and measure them as well.
But few aquarist have this or measure it. Getting them to be the same also presents a problem.
So a good reference tank and good level of culturing competence is required to test such matters. And to produce anything new as far as tolerance of CRS, Cherries, Amano's or fish and plants etc.
The methods are pretty similar for all these wide range of groups.
If you do not have that ability, then you will be suspicious and unsure.
You will question me, and others........but you will learn if you keep at it.
I do not know why some folks have issues, I only know what causes it cannot be, I do not know why X aquarist has dead CRS in many cases.
Sorry, folks do not know everything, but they can learn a little about the possible suspects and rule them out.
I have ADA AS as well, high light and CO2 etc.