API test completely off

[themoeller 7]

If you guys know me by now, I had an apparent spike in nitrates from my tap, well at least according to the api test kit.

I did 12 tests in 2 days and It kept reading between 40-60 ppm nitrates. Same as my tank. So I called the city, they came this morning and tested my water from the tap, and my tank.

5.6ppm @ tap

7.4ppm @ tank

We even re ran the tests several times, same results. Even did the api test kit, came out 40-60 ppm.

So I bought another one this morning. Same thing.

[fantailfan1 26,742]

Try bringing a sample of your tap and tank water to a local pet store. Petsmart and Petco both test for free I believe. I know Petsmart does. See what they get. Tell them your situation and ask for actual numbers, not just "acceptable" or "fair" or whatever.

[DieselPlower 2,123]

How old is your test kit?

[fantailfan1 26,742]

How old is your test kit?

He said he bought a new one this morning and got the same results.

[tithra 4,917]

That's weird. Test some bottled water just to make sure you get a 0 reading

[hollyh 54]

The city could have had bad readings, their equipment does have to be calibrated. They might have messed that up?! But I'd assume/hope that they did that and keep their equipment in good shape and their numbers are good.

When I was having problems reading my API Nitrate test (mine always read zero) I bought the Seachem Nitrate/Nitrite test. It is sort of an easier to use test. And does give you a better low level reading. Maybe try one of those instead of the API?

All that said, not sure what you can do about it even if all of your tests come out different from their results. I highly doubt that they'd believe your numbers over theirs.

[GoldenSpoiledRotten 6,786]

The API has been proven to be the most effective test so far, as far as readings from this forum go.

I have seen this happen before, with the city always coming out quite a bit less than the API kit shows. In fact, this almost always seems to be the case.

I agree that a third opinion is likely going to be beneficial. I would go have it tested at the LFS.

[themoeller 7]

I don't find this or any kit too reliable. Hard to tell which shade things are. Im bringing it somewhere tonight if I have time. We tested everything three times with his kit, same results each time.

ill let you know what I find.

[themoeller 7]

oh and I tested spring water, came up 10ppm nitrates maybe 5ppm.

[fantailfan1 26,742]

The nitrate test is hard to read. But I always say, if it's in the orange/red shades, rather than trying to decipher what the number is, take the time to do a large WC and test again . . . If it's above 20, keep going.

If your tap is over 20, that's another story.

[Moucho+Moncho 402]

My city is always under my test kit readings. I would follow Lisa's advice and test--WC--Test

[LisaCGold 1,691]

Wow, this is disturbing about the differences in the city tests and the api test kit for nitrates. I hope you can figure out this mystery.

I use the Seachem nitrite and nitrate test kit. It contains a reference test which is a small sample of water that one can use to optionally validate the performance of the kit.

[DieselPlower 2,123]

How old is your test kit?

He said he bought a new one this morning and got the same results.

Whoops!

[shakaho 6,312]

Here is the explanation:

Interpreting Test Results

The laboratory will report the nitrate concentration as milligrams per liter (mg/L) or as parts per million (ppm), which are equivalent for the concentrations occurring in dilute aqueous systems, such as: drinking water (1 mg/L = 1 ppm).

Most laboratories report nitrate as nitrate-nitrogen (NO₃-N), which is the amount of nitrogen in the nitrate form. Some labs may report total nitrate (NO₃-). Be sure to check your test report for which quantity, NO₃-N or NO₃-, is reported. Use the following to compare the two reporting systems:

10 mg/L nitrate-nitrogen (NO₃-N) =
44.3 mg/L nitrate (NO₃-)

The U.S. Public Health Service recommended limit of 10 mg/L NO₃-N in drinking water is used by the EPA as the maximum contaminant level for public water systems. Public water systems are legally defined as those that have 15 or more connections or regularly serve more than 25 persons. These systems must comply with the 10 mg/L NO₃-N standard in order to be an approved water supply. EPA requires regular testing of public water systems for nitrate-nitrogen and nitrite-nitrogen and these test results are available from the supplier. If a test indicates that the nitrate-nitrogen concentration of the delivered water exceeds the standard, the public must be notified and treatment must be performed. Often, the treatment may be as simple as blending the water that exceeds the standard with water that has a nitrate-nitrogen concentration less than 10 mg/L such that the average concentration of the delivered water is below the EPA standard.

The city is reporting nitrate-nitrogen. You are reading mg/l nitrate.

Edited September 3, 2014 by shakaho