1) those are dosage rates. You don't test for them, you add enough to make that many PPM in your tank (on top of what's already there). Usually these are specified for some kind of interval, such as daily or weekly with a certain percentage water change assumed on a weekly basis.
2) figuring out your fertilizer, CO2 and lighting levels. From what I've read, most red plants need a good bit of light and iron to stay red.
3) No, but nitrogen is a part of nitrate. Nitrate is NO3. Nitrogen is just N (usually N2 in pure gas nature).
Last edited by mattinmd; 09-26-2014 at 08:08 PM.
Reason: fixed bases to basis