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Discussion Starter · #1 ·
In High Nitrates out of the tap, recent changes I spoke about high nitrates out of our tap water and extremely high values in our tanks. We have more information. I've started a new thread because that other thread talks about dealing with it, here I just want to get some advice.

The problem appears to be with the test kits!

We have 2 kits, one expires in 6 months, one is brand new. (We have his and hers fish rooms...) We we measuring about 10 ppm nitrate out of our tap. This was a brand new measurement. I measured the tap about 2-3 weeks ago and got 0, just like I got 0 in some of our other tanks.

We called the city and they were interested. My wife met them at the waste water treatment plant (they were on site today doing some testing) and brought a sample from yesterday and a sample from today. They measured 1.25 and 1.28 ppm with their Hatch Photospectrometer system.

When she got home we remeasured and were able to repeat out 10-20ppm values with the API test kits. This shows that the "aged" water doesn't release Nitrate, not that I thought it would but we ran the tests for completeness sake.

We've contacted API and I'll let you know what, and if, they respond.
 

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75g, 33L, 2g and play tanks
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could there be a broken line or something between you and the water plant? maybe something is leeching in. did you get to run tests with your API kit while at the plant too? that would be best way to find out if it's the kit or not.
 

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Discussion Starter · #3 ·
Sorry if I wasn't clear. We brought our tap water to them, a Sunday and Monday "pour." Then we retested those same samples when she got home. She only went to the treatment plant because that's where the techs happened to be on their Monday rounds.

Our small town is fed by several wells but they are only running one now.
 

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Discussion Starter · #5 ·
API says

Thank you for contacting API Technical Services. The API Nitrate test kit is designed for use with aquariums and gives you a reading of Nitrate as Nitrate (Nitrate-NO3) rather than Nitrate as Nitrogen (Nitrate-N) which is likely what the water company was testing for.

To convert Nitrate-NO3 to Nitrate-N:
Nitrate-N (mg/L) = 0.2259 x Nitrate-NO3

To convert Nitrate-N to Nitrate-NO3:
Nitrate-NO3 = 4.4268 x Nitrate-N

Using the numbers you provided
Nitrate-N (mg/L) = 0.2259*(5)
=1.1295
So this doesn't explain the dramatic increase in nitrates that we've been seeing in our tank unless, of course, we've both been over fertilizing, which seems weird.
 

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Discussion Starter · #7 ·
And the town says...

The test we ran yesterday gave the results as 1.25 mg/L NO3-N.
The instrument gives you the option of reporting either way.
So both our API kits are not agreeing with the Hatch Photospectrometer. And this is a recent change, we used to measure zero nitrates.

We're following up with API.
 
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