API Test Kits

I bought a new API master kit about a month ago and (At least to my knowledge) have had no problem. Today I tested a friends tank and my nitrate kit read app. 40 ppm. He said the last time he went to the LFS it was fine. So I go through the nitrogen cycle spiel and ask how long it's been since he did a water change la, la la.

Anyway, he does a 10 % water change, buys a API kit and its reads app 5 ppm. I tell him that is really mathematically impossible. He goes to one LFS with a sample and its low app. 5 ppm. he goes to another LFS and gets the same result. We go back to his house and I get 30 ppm.

So obviously my results are jacked. Sort of hard to argue with three against one. The dates on my bottles are 09/09 and 11/09, so I don't think it's age. I know that API kits are not the best but it's what I have.

The question is how can my kit be off that much? And, has this happened to anyone else?

Thanks

 

I would call API.

Contact Us - API

 

Thanks, I sent them a message and we shall see what they say. The web site says that they could take up to four days to respond.

I did a complete test of my water and took a sample to the LFS. Not only were the Nitrates off 30 ppm, but the calcium was off 100, and dkh was off 4 as well.

 

Wow, good to know... I use API for nitrate test, salifert for Cal. Alk. though

 

Where is your water coming from? I had an incidence years ago where my API (good tests by the way) read Cal at 700 ppm. Took a sample to LFS and 2 different tests showed 700 ppm. This was nearly impossible because at the time I wasn't dosing and was just starting to want to get into corals. After about 8 mos. all tests showed cal at 380-400 ppm. I was using RO/DI water but we determined something in the water was throwing the tests off.

 

are you following the directions to the "T".

shake bottle 1 for 10 seconds
shake bottle 2 for 60 seconds
put 10 drops of bottle 1 into tube shake 5-10 seconds
put 10 drops of bottle 2 into tube shake for 60 seconds.
wait 5 minutes for results.

??? makes a difference. my lfs didnt shake for 60 seconds and got a lower reading then what it really was.

 

Great point! I guess I take it for granted people are reading the directions carefully. In your advice here though I must point out that you must shake bottle #2 for (mine says 30 sec.) just prior to adding the 10 drops into the vial and yes, then shake the vial for the full 60 secs. and then let stand for 5 min.

 

I agree.

Also, do you know what the LFS used to test? Several just use test strips and, as we all know, those don't count. IMO, 100:1... if 100 is test strips, I'd still go with the one liquid test kit.

 

I do not have an RO filter. I am getting RO out of the Culligan machine at the grocery store. I do not know if it has a DI unit or not.

 

Oh ya, to the letter. I can personally say the nitrate kit was off, as I used both kits the same way and used a stopwatch for the times.