I know I shouldn't concern too much about the concentration but I want to know if I should dose more NO3 than recommended for a 20-40g tank. I have a 40g tank with maybe 37g of water column.
Currently I am dosing 30ml of NO3 from a 500ml solution added with 2 tablespoons of NO3 (1 tablespoon for a 250ml solution). Every 20ml of NO3 solution is equal to 1/4 dosage. Dosing 20ml of NO3 from a 500ml solution (mixed with 2 tablespoons of NO3) would give me 6 ppm of Nitrate, in a 40g tank. Is that right? At 30ml, my nitrate concentration is around 10 ppm in a 40g body of water?
Today is when I reset of dosing. After the water change and EI dosing, my API nitrate kit is registering under 20 ppm (17 pp maybe). Before the water change, it was less than 10 ppm. I just came home today and my reading about an hour ago was maybe 13ppm, towards the color for the 10ppm. If the tank consumes about 7 ppm per day, I would think that my nitrate would be on the low side just the day before my next dosing.
Now, I have another API kit showing me 10+ppm extra than the other kit.
My bet is that the other kit (the one telling me I am at 13ppm with NO3) is more accurate. If that's the case, I would up my NO3 dosage to 40ml.