# Increasing Specificity of the API tests



## swyftfeet (24 Jan 2022)

Probably a very odd question but can you double specificity of the liquid test kits by adding either half the number of the drops or double the amount of water,  meaning after doing so I would double the resulting match on the card?
contra:
If I added double the drops or half the water would I half the color match?

Are the Test kits linear in this fashion?


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## Hufsa (26 Jan 2022)

I only use JBL tests (and barely at that), but I know they advise in their FAQ (lower down on this product page for instance) that you can double the amount of water, but you must use distilled water for the additional amount. I dont think you can double the drops in the same fashion, although I may be wrong. I will tag @jaypeecee here as he is up to date on all the tests


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## PARAGUAY (26 Jan 2022)

Just follow instruction as given on bottles


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## jaypeecee (27 Jan 2022)

swyftfeet said:


> Probably a very odd question but can you double specificity of the liquid test kits by adding either half the number of the drops or double the amount of water, meaning after doing so I would double the resulting match on the card?


Hi @swyftfeet

I'm not familiar with the use of the word "specificity" when used in this context.



swyftfeet said:


> If I added double the drops or half the water would I half the color match?


I have to confess to not fully understanding your question and the only API tests with which I'm familiar are KH and GH. If you want to improve the resolution of these two parameters, API gives instructions on how to do this.



swyftfeet said:


> Are the Test kits linear in this fashion?


See above.

JPC


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## hypnogogia (27 Jan 2022)

swyftfeet said:


> double specificity


What do you mean by this?


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## Hufsa (27 Jan 2022)

I think OP means for example measuring 0.5 gh instead of 1.0 increments


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## Yugang (27 Jan 2022)

When measuring kH of gH, can use double the water volume, devide the number of drops by 2 to calculate the kH. You then get steps of 0.5 kH, iso 1 kH. But this particular test is when the color instantaneously changes and you measure the number of drops.
For the other tests, with a color scale, follow instructions as to how many drops to add to the prescribed water volume and observe color from chart.


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## swyftfeet (28 Jan 2022)

All  I have a brand new tank that I'm keeping a journal on.   I'm trying to track ammonia levels after water changes and what not.

the problem is I personally cannot perceive very well the difference on the  ammonia chart of the 0.25 the 0.5 and 1.0.  they look very similar under most lighting conditions to me.

So I was trying to make the color change more drastic yet mean something on a linear scale that would be easier to identify.

y= mx +b  where b is 0 (no change in color)

2y = 2mx

that was my thinking...

so if the relationship was linear if doubled the drops in 5ml, then I would expect a 1ppm to look like a 2ppm.

I was always worse than bad at chemistry, so I was asking if I lost my marbles.

@jaypeecee  Sorry if I misused the term specificity.  I often do.  I thought increasing the specificity meant making it more sensitive.
*Biology*

the narrowness of the range of substances with which an antibody or other agent acts or is effective


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## Kelvin12 (28 Jan 2022)

These drop by drop kits always worry me.  Instructions say look down the test tube for comparison but you see photos on this forum of side on shots but the comparisons are like chalk and cheese.  Always the look down comparision is always several stages darker by several points.   Not a good indication for new comers by any means. 
Dirk


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## swyftfeet (28 Jan 2022)

so I keep rereading what I am typing and maybe my equation was left without enough explanation...   

I will preface that I know jack-all about the chemistry of testing kits or how they work besides: magic drops make color happen.  They proclaim to measure some aspect of the water in ppm based on a test sample size of 5ml.   

If I use the same number of drops in 2.5 ml, then it would seem that the color match on the provided scale scale would match to double the actual ppm. meaning the real value of 2ppm would look like 4ppm.    Likewise if I used double the drops on 5ml.

Alternatively, If I used double the volume of water or half the drops, then the color match would have to be doubled.

This would only work like this if the color change could be expressed as a linear eqn.

since the 0 color change indicates 0ppm the y intercept is 0.

Anywho, in the end it doesnt really matter as I am going to wait till ammonia = 0,  I feel like i'm circling the rabbit hole here trying to explain concept that seems obvious to me thinking about it. But I am also failing spectacularly at communicating it.


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## DaveWatkin (28 Jan 2022)

Kelvin12 said:


> These drop by drop kits always worry me.  Instructions say look down the test tube for comparison but you see photos on this forum of side on shots but the comparisons are like chalk and cheese.  Always the look down comparision is always several stages darker by several points.   Not a good indication for new comers by any means.
> Dirk


Pretty sure the look down tube tests are the JBL type that use wide test containers, the API in narrow tubes should be measured side on.


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## Yugang (28 Jan 2022)

swyftfeet said:


> I am going to wait till ammonia = 0


Indeed 

Just a tip - it is sometimes easier to see the color when the solution is observed in a small white bowl. That's how I do the gH test, where I find it hard to see the color change point.


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## Hufsa (28 Jan 2022)

swyftfeet said:


> failing spectacularly at communicating it.



I had another whole useless post written out when I finally realised (maybe?) what you want. 
You dont want a smaller more sensitive reading. You want a bigger one (duh) 
All the advice I can find on test kit use only allows for (smaller) readings that need to be multipled later to get the actual result.
The API ammonia test did not have any useful FAQ that I could find, but the JBL ammonia did, and they appear to use the same color gradient, and therefore I would assume they are based on the same ingredients and reaction. So usage advice for JBL ammonia should then theoretically apply to API ammonia as well.

See FAQ further down on this page
They do not mention doing double drops, but then again the question on their FAQ was for when readings were outside the scale.

You could try it and report back your findings, but to save time and headache I would just wait for it to read a clear 0 as you say.
The hobby has many rabbitholes, and it is sometimes best not to go down too deep 
The 0 reading is a very distinct warm yellow compared to the greenish yellow hues of the scale.
With practice you should be able to tell it quite immediately.


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## Nick potts (28 Jan 2022)

Hufsa said:


> You dont want a smaller more sensitive reading. You want a bigger one



Exactly, they want a larger/stronger colour change for a smaller change in parameters.

Interested to know the answer to this myself, I don't test often but I really struggle with the subtle changes to most kits and have to get others to try and figure it out. KH/GH are about the only ones I can reliably do.


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## dw1305 (28 Jan 2022)

Hi all,
I'm going to tell you the simple answer is to have plenty of plants in active growth, and then you can ignore ammonia (NH3),  it is never going to build up to toxic levels.

I have access to <"an analytical lab">, but even then there are some issues and I don't test for ammonia in the aquariums.


swyftfeet said:


> All I have a brand new tank that I'm keeping a journal on. I'm trying to track ammonia levels after water changes and what not.
> 
> the problem is I personally cannot perceive very well the difference on the ammonia chart of the 0.25 the 0.5 and 1.0. they look very similar under most lighting conditions to me.


You really need a much <"more sensitive measurement method">. Testing for any gas (NH3) <"is problematic">, but with ammonia/ammonium you can convert it to the ammonium ion by lowering the pH (or into NH3 gas by raising the pH).

The two colorimetric methods available are <"the Nessler method"> in which potassium, mercury, and iodine react with  to create a yellow-brownish colored compound and the salicyate method in which "_free ammonia reacts with hypochlorite to form monochloramine. Monochloramine reacts with salicylate, in the presence of sodium nitro-ferricyanide, to form 5-aminosalicylate, a blue-colored compound"_.  The color intensity of the final compound is proportional to the concentration of NH3/NH4+ in the sample, in both cases.

<"An ion selective electrode"> would do, but they are expensive bits of kit and you still need to convert all the <"TAN to the ammonium ion (NH4+)">, or to NH3, before you can get a reading.

cheers Darrel


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## swyftfeet (28 Jan 2022)

Nick potts said:


> *Exactly, they want a larger/stronger colour change for a smaller change in parameters.*
> 
> Interested to know the answer to this myself, I don't test often but I really struggle with the subtle changes to most kits and have to get others to try and figure it out. KH/GH are about the only ones I can reliably do.



*Yay! i don't have to be the guy shouting "I'm not crazy" as the load me into the back of the panel van.*

Ok, I feel better that someone is understanding me.  The color swatches on the test kit ranges from 0 -> 8ppm, what I am trying to do is make that color range represent 0->4ppm.

 if my actual sample is:
0 should appear as 0
0.25ppm actual should match the 0.5 color patch,
0.5ppm  actual it should appear as 1 color patch
1 it should appear as 2 color patch and so on.

I'm trying to make it easier on my eyes since the colors change would be more significant for a smaller range which I called doubling the specificity...

Thank you all for the information and attention, I'll read those links.    I really do get intimidated by chemistry, so there is an opportunity to slay that dragon here I guess.

 I don't think I know any more (yet) than when I started, but I think that's more a reflection on the student than the teachers.


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## Nick potts (28 Jan 2022)

I can't help with the answer to your questions, but if you really struggle with colour like I do, you could look at the hanna pocket checkers, they give you the result on a digital screen


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## swyftfeet (28 Jan 2022)

this is my dilemma. Is that 0.25, 0.5 or 1. Lmao

Doesnt help that they used an inkjet CMYK printer to generate the color swatch.   Even worse the heads arent even aligned.  /sigh

Not that it terribly much matters it isn’t 0. 

But I was trying to keep a diary.


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## jaypeecee (28 Jan 2022)

DaveWatkin said:


> Pretty sure the look down tube tests are the JBL type that use wide test containers, the API in narrow tubes should be measured side on.


Hi @DaveWatkin

You can see from the pictures below how the JBL test kits are used:









						JBL PROAQUATEST PO4 Phosphate Sensitive
					

Determines phosphate value for perfect plant growth or possible cause of algae growth in freshwater/marine water & ponds




					www.jbl.de
				




I like this comparator system. The only exception to the colour comparator (that I know of) in the JBL range is the potassium (K) test kit, which is based on turbidity (cloudiness) but this, again, is done by viewing the tube from above. I can't be certain but my guess is that JBL test kits are very probably manufactured by Macherey-Nagel.

JPC


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## Hufsa (28 Jan 2022)

swyftfeet said:


> Doesnt help that they used an inkjet CMYK printer to generate the color swatch.   Even worse the heads arent even aligned.  /sigh


Wow that print sucks big time, my eyes cant decide if they want to focus on the lighter lines or the darker ones within the color 😂
Based on the picture id say slightly more than 0.5 (~0.6) but pictures can lie.



swyftfeet said:


> But I was trying to keep a diary.


No diary for you lol!
I guess it will have to be "Dear diary, API sucks, forum is no help. >0 Ammonia"


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## jaypeecee (28 Jan 2022)

swyftfeet said:


> this is my dilemma. Is that 0.25, 0.5 or 1. Lmao


Hi @swyftfeet 

It's between 0.5 and 1.0 ppm, as seen on my PC monitor with my eyes. In other words, the water would be toxic to fish and other livestock. Is that the API Test Kit?

JPC


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## X3NiTH (28 Jan 2022)

Using a pixel editor you can see that the 0.5ppm colour swatch has more of the same colour as the sample.


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## Hufsa (28 Jan 2022)

@X3NiTH living in 2122 compared to us


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## swyftfeet (28 Jan 2022)

X3NiTH said:


> Using a pixel editor you can see that the 0.5ppm colour swatch has more of the same colour as the sample.



I came to pretty much the same conclusion I did a 16x16( LOL)  gaussian blur on the swatches  using gimp and was more in the zipcode of .5 than .25  doing droppers on the 3D color map  but didnt think to threshold on the green, back to the books!


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## jaypeecee (28 Jan 2022)

X3NiTH said:


> Using a pixel editor you can see that the 0.5ppm colour swatch has more of the same colour as the sample.


Hi @X3NiTH 

Perhaps API should include a small laptop (with integral webcam) or mobile phone and pixel editor in their test kit! 

JPC


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## swyftfeet (28 Jan 2022)

coming soon with all api test kits starting at $450k


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## hypnogogia (28 Jan 2022)

jaypeecee said:


> Hi @DaveWatkin
> 
> You can see from the pictures below how the JBL test kits are used:
> 
> ...


The JBL tests are certainly amongst the better ones.  Viewing from above as well as using a test tube of tank water to take into account the colour of that.


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## swyftfeet (28 Jan 2022)

well I tested 8 drops of magic in 2.5ml (instead of 5ml) and the color went the other way than what I expected.  looks more like .025 than 1 now. 

I'm clownshoes at this stuff.

maybe I should stick to the league I can hit the speed of the pitch and get some danios with plastic plants.  😂


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## Hufsa (28 Jan 2022)

swyftfeet said:


> I'm clownshoes at this stuff.


Nah mate, now we know that it doesnt work and the next guy who asks we will show this thread


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