help reading my hanna nitrate meter?

[JackBlasto]

I got a hanna nitrate monitor for my planted freshwater tank. It states in the instructions

"at the end of the measurement, the instrument directly displays concentration in mg/L of nitrate-nitrogen on the LCD."

Now, the part that I am confused by is it goes on to say

"To convert the reading to mg/L of nitrate (NO3), multiply by the factor of 4.43"

Well, the meter reads 10.8 so I'm guessing based on what's being stated that that's 10.8 mg/L of nitrate- nitrogen

Being that I want to know nitrate levels if I multiply that by 4.43 I get 47.84 which is crazy high if I actually needed to do that conversion? 10.8 sounds right to me and my stick test still reads the nitrate white on the stick (meaning it's most likely actually 10.8... thus it's not picking it up)

QUESTION, is the 10.8 the number I'm looking for when looking for nitrate levels in my planted tank OR is it the 47.84 to which I don't have any clue what it's reading that high unless I should have never done the conversion?

I understand I want my nitrates to be between 10 and 20 ppm in a planted tank so my reading of 10.8 is great but if I'm supposed to pay attention to the 47.84 I'm not doing good at all.

I know there are some really great science oriented people out here on this forum that can advise me. Thank you for any help.

 

[aqua_chem]

Nitrate nitrogen is just the contribution of nitrate to the total available nitrogen, with total nitrogen being equal to ammonia nitrogen plus nitrite nitrogen plus nitrate nitrogen. You need to multiple what your meter reads out by 4.43 (the inverse of the mass fraction of nitrogen in nitrate) to get nitrate.

 

[JackBlasto]

Thank you. Now can I assume that when I read that planted tanks should be between 10-20 ppm nitrate levels they ACTUALLY mean that nitrate levels should be between 44.3 - 88.6 ppm and the nitrate-nitrogen level should be between 10-20 ppm?

 

[aqua_chem]

No, it means that nitrate should be 10-20 ppm and nitrate nitrogen should be 2-5 ppm.


All of our rules are centered around nitrate. Nitrate nitrogen usually only comes up when someone is comparing different measurements (ie nitrate ppm vs ammonia ppm), using something not designed for the hobby (like your meter) or someone trying to look smart.