Truth be told, you don't have to try and shame me into learning. Not when I'm already here trying to do just that.
Thrill,
I'm not trying to shame you or anyone mate. I want you to see the truth, and I'm having to reveal the same truths for decades now. There are companies out there who only care about money, so they will tell you anything in order to win your cash. Test kit companies are one of them. And they don't care whether you succeed or not because there is always another fish on the hook. They will get rich.
I care that you know the truth and that you spread the truth. Isn't that what the Matrix films are all about? I think the analogy is apropos, and that's why I use it. It's not about playing mind games. It's about giving you something to hang on to.
So for example, that whole business about inverts not liking nitrates is another illusion. Check my post in this thread
http://www.ukaps.org/forum/threads/ferts-causing-high-nitrate.16092/#post-167069
So that claim is all rubbish, but folks swallow it hook line and sinker, so it trains them to be paranoid about NO3 when they really don't have to be. That illusion then becomes their opening gambit. So what I'm trying to force you to do is to ignore those things that don't really matter and to spend your energy on the things that really matter.
So lets think about the scenario you mentioned for a moment. Adding more NO3 drives more growth and more CO2 uptake. So the plants will remove mor toxic CO2 from the tank. Good for shrimp. Adding more NO3 drives the photosynthetic apparatus faster and produces more Oxygen in the water column. Good for shrimp. More Oxygen is also sent to the roots, feeding the bacteria that convert ammonia in the sediment to NO3 and reducing the toxicity of the sediment to shrimp that are rummaging around in the sediment looking for food.
Furthermore, the plants will uptake NO3 and NH3/NH4 from the sediment as well as from the water column, so even if your test kit were consistently accurate you would not be accounting for the vast stoores of Nitrogen compounds in the substrate. So you whatever number you come up with will not be accurate.
NO3 uptake rate is also dependent on CO2 uptake. The more CO2 you add the more NO3 will be removed from both water column and sediment.
NO3 uptake rate is also a function of PAR. What PAR you have on one tank will not necessarily be the same as another tank, so you could not transfer the data.
NO3 uptake will also be a function of temperature, which drives the metabolic rate.
NO3 uptake rate will also be a function of PO4 uptake, so that if you dose more PO4 then this will drive a higher NO3 uptake rate.
NO3 uptake rate will also be a function of plant mass, more mass requires more of everything. Whatever number you measure today will not be valid a month from now, unless you can maintain the same mass both above or below the substrate.
So, because NO3 production and uptake vary wildly with all these different factors - and also each of these factor have are interrelated with each other (i.e. each has an effect on the other) it becomes a hopeless exercise to draw any kind of general conclusions and to then apply it to another tank.
When T. Barr did his experiments to find the answer to this same question about uptake rates, he had to be very precise and had to isolate many different factors that had an effect. None of us have this level of laboratory control. So tanks, as a system, can uptake anywhere from a few ppm per week to 5pp or even 10ppm per week. Which number is applicable to any one tank? And how can you base a dosing program not knowing where any particular tank sits in this range? And how much NO3 do you have to actually dose in order to achieve any specific rate?
This is specifically why I stated that if you wish to believ that your tap water is high in NO3, then simply delete or significantly reduce the KNO3 input and add K2SO4 so that you don't fall behind on K. Many people do that - but why bother, when shrimp do not really care anyway? London Dragon had a shrimp tank where he miscalculated the dosing and was adding 10X EI. There were no issues.
Other EI dosers have no difficulty attributable to their high NO3 dosing. The empirical evidence is there.
So all of this long winded explanation is to convince you that you do not need to try this, and if you did you would be wasting energy because you cannot control the factors, and even if you did miraculously find an accurate number ,it would not be applicable to anyone else's tank or even applicable to your tank on another day.
Cheers,