API nitrate test kit inaccurate?

[Jade.a.deacon]

Been testing my nitrates in my tank with the API test kit I brought from my lfs, nitrates have been reading very high 20ppm-40ppm but when I take it to local fish store they tell me that my nitrates are perfect at 0ppm. Is my testing kit inaccurate? Have people been having this problmw? I make sure I follow instructions spot on. Any suggestions?

 

[robbrouse]

Did you check the data and make sure they are still good?

 

[Jade.a.deacon]

They expire in 2018 so got a while to go yet lol!

 

[glb]

I used API for a long time and didn't find it too helpful with corals because the ranges on the color card were so big. I got a salifert and find it much easier to read. If you want to finish the API kit before you get another one, look for consistency in the readings and perform the test exactly the same way every time. Remember, consistency is more important than a particular number.

 

[Jade.a.deacon]

Thank you gonna stick to testing at fs for a while I think then I shall get more! X

 

[robbrouse]

The real question here is it your test kit of the LFS test kit that's giving the wrong reading?

 

[Jade.a.deacon]

That's what I wondered but they have display tanks perfectly healthy with all kinds of corals n fish, most of them own marine tanks themselves so surely they must be getting it right?

 

[glb]

That's what I wondered but they have display tanks perfectly healthy with all kinds of corals n fish, most of them own marine tanks themselves so surely they must be getting it right?

Do you know what test kits they used to test your water? It's also possible they use different tests for their display tanks.

 

[Jade.a.deacon]

They do use different test kit but my kit is hard to read anyway all colours are very similar...

 

[beaslbob]

Check both tests to see if they read total nitrates (api kit) of just nitrate-nitrogen. the conversion factor is 4 plus some change. So 20ppm api would be 5 nitrate-nitrogen.

Also the api test kit (i believe) is thrown off if you have nitrItes present. But ususally that is not much of a factor.

my .02

 

[Eienna]

My API kit seems to be accurate enough thus far....I could use smaller-increment readings, though.

 

[dwilliams87]

Check both tests to see if they read total nitrates (api kit) of just nitrate-nitrogen. the conversion factor is 4 plus some change. So 20ppm api would be 5 nitrate-nitrogen.

Also the api test kit (i believe) is thrown off if you have nitrItes present. But ususally that is not much of a factor.

my .02

So, the api nitrate kits results are actually a quarter of what they say it is? Could you please explain thus a little further?

 

[Jade.a.deacon]

I have no nitrites in the tank or ammonia it's all on 0 apart from nitrates which at home in the test kit are 20/40 and at fish shop there is nothing. I can't imagine they are doing anything wron they have experience in this thy have their own marine fish at home and test a lot of people's water? Whereas I am a newbie so it is prob me not them but I follow all instructions so it must be the kit? X

 

[beaslbob]

So, the api nitrate kits results are actually a quarter of what they say it is? Could you please explain thus a little further?

no.

Actually you got it backward as well.

Both api and nitrate-nitrogen test kits are accurate. Just calibrated to measure different readings. There are 4+ some change total nitrates for each nitrate nitrogen. But both are the same nitrate ion. Just one measures the total ion the other is just the nitrogen part of it. So all it really is- is just a calibration difference.

api nitrate of 80ppm would be 20 ppm minus some nitrate-nitrogen.

my 02

 

[rgoodson]

I have had three different instances of the ATI nitrate test kits being inaccurate once the rrgent is about half empty. They show FAR too high. I get a new kit and problem solved. This has led me to believe the regent expires way before the experation date.This is in both freshwater and saltwater tanks. Think I am going to a new brand for my nitrate tests.

 

[Randy Holmes-Farley Verified Community Expert]

I have had three different instances of the ATI nitrate test kits being inaccurate once the rrgent is about half empty. They show FAR too high. I get a new kit and problem solved. This has led me to believe the regent expires way before the experation date.This is in both freshwater and saltwater tanks. Think I am going to a new brand for my nitrate tests.

Expiration dates for many things mean the unopened product (milk, for example). Once opened they may go bad a lot faster, although I've not specifically heard any kit manufacturer say that applies to their own kit.

 

[Upinthinair]

Been testing my nitrates in my tank with the API test kit I brought from my lfs, nitrates have been reading very high 20ppm-40ppm but when I take it to local fish store they tell me that my nitrates are perfect at 0ppm. Is my testing kit inaccurate? Have people been having this problmw? I make sure I follow instructions spot on. Any suggestions?

Did you ever get this figured out? I’m having same issue. I thought it was the LFS so I went to another today and their reading matched the other LFS of around 30. So I came home and tested nitrate and got 80. My Hannah read 63 this morning. I did notice that the LFS wasn’t measuring the time, and the API is particular about 30sec, 1 min, and 5min being important. Thoughts?

 

[Randy Holmes-Farley Verified Community Expert]

It is not uncommon to have testing issues. Folks using just one kit are often just blissfully ignorant. lol

In general, yours are all likely fine but some corals may benefit from the levels being lower. Exact values are not that critical, IMO.