API Nitrate test kit false positive?

[Anubisxii]

I randomly have nitrate's through the roof. Readings of 80-180 on API test kit, 2 different ones. Is there such thing as is nitrates being low and API kit giving a False high reading? I am going today to by another brand test kit but I'm just curious if anyone has seen something to this effect. Bottles are not expired until 2022, doing the test as per instructions as I've always done.

Again just wondering, I thought I heard (read on r2r) that API kits don't handle a low reading well but I can find anywhere now that states that, so looking if anyone has any .02 to add.


Thanks,

 

[Xjv152]

I have had the same problem, test shows zero / yellow and 3 days later it is 80 plus / red. Hope we can get some answers on this. I did order a Sailfert test kit see what that says when it arrives.

 

[BanZI29]

It is possible to get a false reading on API kits of all types if the instructions are not followed EXACTLY. ( from what an API rep told me) if you suspect a false reading, try it again and see what happens. if it does not match the first test, try it a third time and see what happens. I use API tests and I have suspected false readings too. I usually do the same test up to 3 times and compare. According to the API rep, you also have to make sure you hold the bottle straight down and apply equal pressure on the bottle to ensure you get equal sized drops.
It's a pain sometimes but it is the cheapest and I think the easiest tests to use if you do it exactly right.

Also yes API's do have a bit of an issue with reading low readings, especially on Phos and ammonia test. I did buy the Hanna ULR phos test. The others like nitrite, nitrate, pH, ect, I have not had issues with low readings. I have been able to figure out what the reading is.
I use a white light LED lamp when I check the color cards. I can really see the color differences with that lamp and it helps figure out where things really are..

 

[Anubisxii]

It is possible to get a false reading on API kits of all types if the instructions are not followed EXACTLY. ( from what an API rep told me) if you suspect a false reading, try it again and see what happens. if it does not match the first test, try it a third time and see what happens. I use API tests and I have suspected false readings too. I usually do the same test up to 3 times and compare. According to the API rep, you also have to make sure you hold the bottle straight down and apply equal pressure on the bottle to ensure you get equal sized drops.
It's a pain sometimes but it is the cheapest and I think the easiest tests to use if you do it exactly right.

Also yes API's do have a bit of an issue with reading low readings, especially on Phos and ammonia test. I did buy the Hanna ULR phos test. The others like nitrite, nitrate, pH, ect, I have not had issues with low readings. I have been able to figure out what the reading is.
I use a white light LED lamp when I check the color cards. I can really see the color differences with that lamp and it helps figure out where things really are..

I appreciate the info, Let me ask you this when you check the vile against the card are you touching the vial to the card or holding it away? I'm wondering because I do notice it show different colors if you rest the bottle against the card.

Thanks,

 

[Anubisxii]

I was going to get the Hanna nitrate checker but then I was told you have to delude it when readings are over a certain amount and I just don't trust myself to be 100% when doing that. I am going to go to a few of my LFS's today and see what options they have available.

 

[Flux Capacitor]

I was going to get the Hanna nitrate checker but then I was told you have to delude it when readings are over a certain amount and I just don't trust myself to be 100% when doing that. I am going to go to a few of my LFS's today and see what options they have available.

While this is true to some extent, remember these are hobby grade tests. You can run the test undiluted up to 5ppm, which is where you really want the accuracy if you are keeping your nitrates that low. However, if you dilute the test, and let’s say it tells you 10ppm, is your response to those nitrates gonna be any different than getting 12ppm or even 15ppm due to diluting error?

 

[BanZI29]

I appreciate the info, Let me ask you this when you check the vile against the card are you touching the vial to the card or holding it away? I'm wondering because I do notice it show different colors if you rest the bottle against the card.

Thanks,

I dry off any water that is on the vile and then hold it against the card right at the edge of the color blocks. For me, that is the easiest way to see the color differences between the color blocks and the vile.

 

[Zach B]

I have had api tell me my nitrates were way high, retested with salifert and it was fine. I guess some are bad and some are decent

 

[Deschutes541]

I was going to get the Hanna nitrate checker but then I was told you have to delude it when readings are over a certain amount and I just don't trust myself to be 100% when doing that. I am going to go to a few of my LFS's today and see what options they have available.

I have the Nyos kit and I like it far more than API. It's pretty simple to use.

 

[Spare time]

If you have nitrite present somehow, that might throw it off.

 

[jrill]

People often mess up with the API nitrate test by not shacking bottle 2 long enough. it really needs to be mixed well

 

[Timfish]

I like APIs pH, calsium and especially their Alkalinity test kits. But I've had their Nitrate give erroneous readings. One thing I've noticed is it seems to be pretty sensitive to heat. With all my test kits I have multiple kits for each parameter on hand and I always check new kits against old kits to reduce the risk of bad reagents.

 

[Bluenote]

Also keep in mind when you are shaking the vial that the lid is on well. Ive thrown out some lids that have somehow changed size over time and allowed both liquids in and out.

 

[nashvillian]

I use a plastic pipette to mix the solution with both reagents, drawing it in and out carefully for the duration of 60 seconds. You can lose a lot of solution mixing with the lid on and shaking it.

 

[HawkeyeDJ]

I appreciate the info, Let me ask you this when you check the vile against the card are you touching the vial to the card or holding it away? I'm wondering because I do notice it show different colors if you rest the bottle against the card.

Thanks,

Hold the vial a couple of centimeters away from the chart. Your light source should be relatively bright and coming over your shoulder. Look at the water sample through the center of the vial, ignore the curved edges.

I get my first reading against the white background and pick the number from the chart. I then pass the vial over the colors and the one that is the least visible through the vial confirms my first pick.

And remember, these home tests, regardless of brand, are ball park accurate only.

I don't know how often you run your tests, but always record them somewhere. That way you will see trends and recognize sudden deviations.

 

[BruddahMan]

I have had api tell me my nitrates were way high, retested with salifert and it was fine. I guess some are bad and some are decent

I was having repeatedly high Nitrate readings with API…..took sample to my LFS who tested sample (I believe with API, too) and it was the beautiful yellow we want. Also, it stayed yellow over a 10 minute period, unlike my home tests which just kept getting darker over the same period. I believe there may be an issue with API’s reagents.