Problems with Nitrate testing with API marine test kit

[rhininiho]

Hey all,

I have my tank up and running for about 4 months now and all seems fine, during the first few months I was bringing a water sample to the LFS each week to get some premixed salt water for the water changes and all the readings were in check. I decided to get a test kit as I wanted to take more control over this part of my tank and the more I read up on this the more important I realised this is.

I have tested the water for the last two weeks with this API test kit I got and the results are as follows
PH 8.2-8.4
Ammonia 0ppm
Nitrite 0ppm
Nitrate 20-40ppm according to the scale.

I brought a sample to the LFS and asked them to test the Nitrate last week when I had read the levels above. They tested the Nitrate and the scale measured 5-10ppm. I don't know what testing system they use, it is power in tubs.

I have tested the water last night myself and got the same results as above for all.

Has anyone else experience with such a difference between test results. The fish I have all seem to be fine and lively and are behaving as expected based on the research I have done.

 

[rhininiho]

Also I am conducting around 15% water changes every 10days or so.

 

[neilanh]

could be a variety of factors. Age of one of the test kits, temperature of the test regeants, temperature of the water, etc etc.

You have to remember these are all hobby grade test kits, they're not entirely accurate, but good enough for our purposes.

I assume you have some fresh RODI water laying around. Just for kicks, test it and see what you get.

 

[rhininiho]

Yeah have some here so was thinking of checking it tonight alright.

 

[hdultra]

Hey all,

I have my tank up and running for about 4 months now and all seems fine, during the first few months I was bringing a water sample to the LFS each week to get some premixed salt water for the water changes and all the readings were in check. I decided to get a test kit as I wanted to take more control over this part of my tank and the more I read up on this the more important I realised this is.

I have tested the water for the last two weeks with this API test kit I got and the results are as follows
PH 8.2-8.4
Ammonia 0ppm
Nitrite 0ppm
Nitrate 20-40ppm according to the scale.

I brought a sample to the LFS and asked them to test the Nitrate last week when I had read the levels above. They tested the Nitrate and the scale measured 5-10ppm. I don't know what testing system they use, it is power in tubs.

I have tested the water last night myself and got the same results as above for all.

Has anyone else experience with such a difference between test results. The fish I have all seem to be fine and lively and are behaving as expected based on the research I have done.

It doest'nt seem all that far off, Some tests from diffrent manufacturers read diffrent than others.
Or maybe your sample got contaminated somewhere along the line.
I would trust my own API Test Kit. My readings seem to be stable or do not change with 2 straight test. Just my thought, other members may have some other ideas.

 

[rhininiho]

I tested the LFS premixed water and the Nitrate is 0ppm so i have to assume the test kit is ok.

So I guess the next thing is to do is to increase frequency of water changes to see if that will bring down the nitrate level.

Any other suggestions?

 

[hdultra]

I'm assumeing you have African Cichlids with that PH Range. Safe nitrate level would be around 20

 

[mellowyellow]

The same happens to me with Nitrite levels. If it shows higher than I want, I rinse out the tube and try again. Then, it shows 0. There must be some truth to the temp of the water as Neilanh suggested.

 

[jacobzking]

also be sure that you are using the appropriate fresh water or saltwater test charts. with the API kits for example, the testing solutions are the same, but the color charts are different for fresh water and saltwater

 

[mellowyellow]

Thanks. You're right. I have a fresh tank upstairs on the second floor and a freshwater kit upstairs also so that I don't get confused. It's one less thing to think about.