Hanna HR Nitrate Checker - How to dilute if over 75ppm?

[adamf83]

I purchased the Hanna HR Nitrate checker and my first test came out flashing 75ppm, so outside of what the device can read. The instructions say to dilute the sample and repeat, but it doesn’t say by how much.

Has anyone ever done this in order to get an accurate reading?

 

[mdb_talon]

Never done it but should be able to use 5ml tank water +5ml rodi. Test and then double the result it gives you

 

[Neil Cohen]

Just had to dilute 2ml tank water, 8ml rodi to get a reading. Came out to 41.2, multiplied by 5 and can't see how that is correct. How can I have 212 ppm NO3 and still have anything alive? Have to be doing something wrong.

First thought was perhaps I reversed the dilution. That would give me around 50 but then the tester would have read it rather than blinking 75.0.

Heading to the LFS. Not loving the hanna. Grrrr

 

[Randy Holmes-Farley]

As I mentioned in the other thread, there is a salinity effect on nitrate testing, making dilution imperfect.

 

[Neil Cohen]

Thank you. Makes sense, don't know how much it affects my number but it is still quite high.

 

[Billldg]

If its over 75 then I would not worry about diluting it, I would first try to get it down so it will read properly.

I also have a HR Hanna and never read where it said to dilute it. Again, I would try to get it lower. I also pegged out my Hanna initially, buy thru some water changes I was able to start to get it to read below 75.

 

[Neil Cohen]

Working on it. The reason I am reg checking is to monitor the carbon dosing