# How to read API nitrates liquid test ?



## Diana (Jan 14, 2010)

I do not hold it right against the card. 

Be sure to REALLY SHAKE the reagent bottles.


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## candymancan (Nov 1, 2014)

I do for like a minute or two


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## roadmaster (Nov 5, 2009)

I put away nitrate test a couple year's ago when I started dosing nitrogen and noted 80 ppm a day after dosing.
Shrimps,rummy nose (canaries of the aquarium) still thrive so I don't worry bout nitrate levels.
Nitrates prolly closer to 60 ppm by week's end in my tank's which is when I perform water changes and re dose.
Is said that without calibrating the Nitrate test (can google this) that reading's are at the very least suspect, to outright erroneous.


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## candymancan (Nov 1, 2014)

well I have discus and electric blue rams which are sensitive to nitrates..


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## PlantedRich (Jul 21, 2010)

One of the reasons I do not recommend the liquid tests for novices is the number of ways to mess up the results. I may agree that long term testers who know what to expect from the results may be able to get more accurate results with the liquid tests. But when a person is newer, there are just lots of ways to mess up so that the results can be totally meaningless. 
Holding the bottle totally vertical to get the right size drops, counting the drops and making sure they all get into the test vial, shaking before use, using a consistent light source and timing can all be blamed when the reading doesn't come out as expected. But that leaves the newer person with no idea of what to expect in very difficult situation of not knowing he is being mislead by his testing. 
I feel there are times when getting slightly less precise readings from strips can get you a far closer answer than a test which is difficult to do correctly. Most should admit that the test is a "best guess" in either case when you are judging colors on a chart. 

How to hold the tube to read the colors? Everybody seems to have their own favorite way as the directions often don't say.


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## mattinmd (Aug 16, 2014)

In general, I would take the API nitrate test with a huge grain of salt. It is notorious for being miscalibrated. If you want to actually get workable numbers out of it, make yourself calibration solutions, test those, and re-mark your chart.

With my API nitrate test it claimed my municipal tap water supply was 20ppm, source and other testing claims 3ppm. I made a 20ppm reference solution and the API said that was over 80ppm, but less than 160ppm (other test said something near but under 25ppm). And yes, I followed the directions precisely and used a timer for all the shaking, etc. I have found that it does work quite consistently, as long as it is used correcty it always produces the same color for a given ppm, test after test. However, those colors are very different than the chart.

Long story short - don't worry about which of the two squares it is. The test itself may be miscalibrated by a much larger margin than that.

Use the test for relative comparisons only, or calibrate it if you want useful numbers.


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## roadmaster (Nov 5, 2009)

candymancan said:


> well I have discus and electric blue rams which are sensitive to nitrates..


 
It is the biological oxidation of ammonia to nitrites and finally nitrates that fishes don't enjoy.
With KNO3 as dry mineral salt,there is no biological oxidation of ammonia first so increase in nitrate reading due to addition of KNO3 is of no concern for many/most.
I will agree that in fish only tanks, where the biological oxidation of fish waste,fish food takes place , no plant's to help take up the waste,that high nitrate levels are indication of over feeding,over stocking,under filtration,and or poor maint and these should be rectified for the health of the fishes.
Studies indicate that hundred's of ppm of nitrates over prolonged periods are needed before fishes begin to show negative effect's but if tank's are run properly,,these hundred's of ppm are not a problem/can't be.
Adding the dry fertz DOES however increase TDS along with everything else we add to the tank from fish food's,med's,conditioner's,buffer's,etc so maybe for some sensitive species of fishes/shrimp's some reservation may be consideration. IMHO


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## lee739 (Oct 12, 2014)

I made up a reference solution of some KNO3 - at 80ppm - the colour chart did agree - but it is pretty difficult to see the gradation of colour, and it is highly variable based on the light you are using.
Better to think of nitrate readings as zero, low, medium, high I think... you'll be less frustrated!

Best to do as mattinmd alluded to is to make up some solutions of known concentration, and test them all in parallel, then you'll know how your kit reacts.


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## GrumpyGills (Jun 20, 2014)

Another thing to do is dilute your tank water with tap water and test that, then back calculate the nitrates in your tank water.


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## greaser84 (Feb 2, 2014)

You should calibrate the test first http://www.plantedtank.net/forums/showthread.php?t=83545&highlight=calibration Its hard to match the color's if I hold it against the card its one color, if I hold it to the kitchen light its another color, if I hold it to the dining room light its another color. As long as it appears in the 10-20ppm range, I know my plants aren't going to run out. Its always better to have too much than not enough.


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## candymancan (Nov 1, 2014)

PlantedRich said:


> One of the reasons I do not recommend the liquid tests for novices is the number of ways to mess up the results. I may agree that long term testers who know what to expect from the results may be able to get more accurate results with the liquid tests. But when a person is newer, there are just lots of ways to mess up so that the results can be totally meaningless.
> Holding the bottle totally vertical to get the right size drops, counting the drops and making sure they all get into the test vial, shaking before use, using a consistent light source and timing can all be blamed when the reading doesn't come out as expected. But that leaves the newer person with no idea of what to expect in very difficult situation of not knowing he is being mislead by his testing.
> I feel there are times when getting slightly less precise readings from strips can get you a far closer answer than a test which is difficult to do correctly. Most should admit that the test is a "best guess" in either case when you are judging colors on a chart.
> 
> How to hold the tube to read the colors? Everybody seems to have their own favorite way as the directions often don't say.


 
Well the thing is im not NEW ive had fish tanks for 20 years now.. The pupose of this post was to ask what the proper way of reading the test is... Hold it against a white background on the chart itll read 1 step higher then when you hold it an inch away.. So if it reads 10ppm an inch away itll read 20 against, if it reads 20 an inch away itll read 40 against..

I use sunlight as its the best light to get the color...

Bump:


roadmaster said:


> It is the biological oxidation of ammonia to nitrites and finally nitrates that fishes don't enjoy.
> With KNO3 as dry mineral salt,there is no biological oxidation of ammonia first so increase in nitrate reading due to addition of KNO3 is of no concern for many/most.
> I will agree that in fish only tanks, where the biological oxidation of fish waste,fish food takes place , no plant's to help take up the waste,that high nitrate levels are indication of over feeding,over stocking,under filtration,and or poor maint and these should be rectified for the health of the fishes.
> Studies indicate that hundred's of ppm of nitrates over prolonged periods are needed before fishes begin to show negative effect's but if tank's are run properly,,these hundred's of ppm are not a problem/can't be.
> Adding the dry fertz DOES however increase TDS along with everything else we add to the tank from fish food's,med's,conditioner's,buffer's,etc so maybe for some sensitive species of fishes/shrimp's some reservation may be consideration. IMHO




Clearly you don't have Discus or rams.. Those fish cant handle houndreds of PPM of nitrates and honestly.. neither can regular fish... I've had fish get diseases easier once the nitrates get around 80-100ppm and you leave it like that. 

As for rams, any higher then 40-60 and they don't live very long, and with discus.. they stop eating and get sick and hide once the nitrates get above 20 for long periods.. I Keep my nitrates at 5-20 depending on how much the water changes removed.. I tend to do 70% water changes every 4-5 days and by then my nitrates look like they are at 20, after the change they are a very pale orange which looks like 5-10 on the chart

As for ferts I don't use dry ferts I use Liquid, I dose Iron, Pottasium, and flourish every week and I dose excel once a day..

This is my tank btw well one of them I have 8 planted tanks


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## Fodder (Sep 15, 2014)

candymancan said:


> Are you suppose to hold the vial right on the white background of the plastic thing, or do you hold it slightly away from it





Diana said:


> I do not hold it right against the card.


 Agree with Diana. Not sure it makes for more accuracy in technical terms, but it helps me differentiate one step of the chart to the next.



candymancan said:


> Clearly you don't have Discus or rams.. Those fish cant handle houndreds of PPM of nitrates and honestly.. neither can regular fish


 Perhaps this is one of the justifications for water changes. Those levels wouldn’t ordinarily be reached with typical water changes.


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## fishhes (Oct 18, 2014)

I have been skeptical about my test results since I started using the API testing kits. I think they are great for determining the Ammonia and Nitrite levels, but the Nitrate is difficult to read accurately. I test my water regularly and use the same light to read the tests held lightly against the card backing.

To further complicate the issue, my tap water tested at levels between 40-80 ppm. This is rather high for tap water, although 40 ppm is allowable, and it makes me think that the API test is not that reliable.


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## lee739 (Oct 12, 2014)

I was wondering if my test kit was even working, could never record anything convincing from my tank for nitrates.... so I checked the LFS water in the bag of fish one day - well and truly over 100ppm. It was working!


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## roadmaster (Nov 5, 2009)

candymancan said:


> Well the thing is im not NEW ive had fish tanks for 20 years now.. The pupose of this post was to ask what the proper way of reading the test is... Hold it against a white background on the chart itll read 1 step higher then when you hold it an inch away.. So if it reads 10ppm an inch away itll read 20 against, if it reads 20 an inch away itll read 40 against..
> 
> I use sunlight as its the best light to get the color...
> 
> ...


 
You would be mistaken in your assumption that I have never raised Discus or mikrogeophagus.
It is not the number arrived at with nitrate test that is harmful, but the method/process by which the nitrates arrive (ammonia,nitrites,and finally nitrates )as processed from organic waste.
Simply cannot have nitrates in excess with regular weekly water changes or two or three weekly water changes as needed for young Discus unless as mentioned ,,fish are grossly overstocked,over fed,and or maint is lacking.
The Discus in photo is in my view poor specimen as evidenced by egg shape ,and bug eyed= stunting already taking place.
Young healthy discus will be well... Discus shaped/round ,,and eyes should appear small on the head.


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## dmagerl (Feb 2, 2010)

I found that the best way to read the test is not to use a point source light.

Don't use sunlight, it's a point source and the test tube just focuses that source into brighter and darker colors that causes problems interpreting the test.

If you use fluorescent lighting to light your tank, stand/sit close to the tank with your back to it and use light from the fluorescent tube to illuminate the test card with the test tube held firmly against the card. 

Assuming its a 4ft long fluorescent tube, light now hits the test tube from a wide range of angles, keeping the test tube from focusing the light and providing even illumination of the card.


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