# API test kits - check your lot number



## Diana (Jan 14, 2010)

So the old Nitrate tests will read too high? 

The old GH tests do not change color no matter how soft the water, no matter how many drops I add. 

Reminder to all who use these, follow the instructions about shaking reagents and test tubes. Shake REALLY WELL.


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## Darkblade48 (Jan 4, 2008)

Seems unusual; I've used older API nitrate test kits and they still read the same as newer test kits (both calibrated against reference solutions I made in the lab).

I think, as Diana mentioned, one of the main issues is to shake, shake, shake.


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## jeffkrol (Jun 5, 2013)

MrSlumpy said:


> This is just a heads up to those who may be using an older API Freshwater test kit. Here you can see the difference in nitrate test results (same tank water, same time) between a test kit manufactured 6/2011 and one from 4/2013:
> 
> 
> 
> ...


Hmm interesting.. I've always had high nitrates.. (or not.. )


I have more of a beef w/ the ammonia test. Mine is NEVER yellow, even using bottled water.. always a "tint" of green.. Went so far as to put an ammonia "sticky" inside the tank.. which is always yellow BTW..

deleted wrong number.. I've got an expiration of 10- 2017


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## MrSlumpy (Jan 4, 2013)

Darkblade48 said:


> Seems unusual; I've used older API nitrate test kits and they still read the same as newer test kits (both calibrated against reference solutions I made in the lab).
> 
> I think, as Diana mentioned, one of the main issues is to shake, shake, shake.


I did, the old and the new kits were shaken fiercely for about a minute. Both bottles.


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## MrSlumpy (Jan 4, 2013)

Tested again yesterday after doing a water change. tried all the tests from both kits (except the high-range pH.) None of the tests showed a discrepancy except for the nitrate:










My new kit shows an expiration date in 2018, 5 years after manufacture. If I apply that to the old kit (manufactured in 2011) it should have been good til 2016.

So anyway, I think the moral of the story is simply _don't trust the expiration date on API nitrate test kits._ If your nitrate is off the chart, try another kit before you panic.


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