API Marine tests for freshwater

[RandomFactoid]

Hi!

Recently bought a used setup and the API Saltwater Master Test Kit came with it. Any idea if tests are in some way adjusted for salinity ? Can I trust the ammonia/nitrite/nitrate readings in my freshwater tank? I'm thinking that all the tests do is quantify the amount of different ions, so it should be fine...or not ?

Thanks!

 

[MichaelJ]

Although the Nitrate/Nitrite/Ammonia tests in the Saltwater master Test Kit are exactly the same solutions as the ones for freshwater (If you buy the tests individually, the box says for Fresh and Salt water) the accompanying color chart that you use to interpret the reading for the Nitrate and Ammonia tests are different between salt and freshwater, so you wont be able to interpret the reading unless you use the chart designated for freshwater (or look up the corresponding scales online). The pH test in the Saltwater Master kit is only for high range pH (7.4-8.8) and the color chart is different as well.

The only test that is the same is the Nitrite test which uses the same chart regardless of water type.


Cheers,
Michael

 

[hypnogogia]

the accompanying color chart that you use to interpret the reading for the Nitrate and Ammonia tests are different between salt and freshwater

so are they calibrated differently?

 

[dw1305]

Hi all,

so are they calibrated differently?

You can get interference from the chloride ions (Cl-) for the anions (NO2-, NO3-). There is a large (and known) amount of chloride in sea water, so you can take this into account. The same for ammonia (NH3), all the TAN is NH3, because of the pH level and in this case it is the same arrangement but, with a high (and known) level of sodium (Na+).

cheers Darrel

 

[MichaelJ]

so are they calibrated differently?

I suppose so. When looking at the two different charts for the Ammonia test (below) it appears to me that the color swatches are basically offset between the two water types (the solutions and amounts going into the test tube are identical regardless of water type):

Cheers,
Michael

 

[hypnogogia]

Shame I can’t see the numbers and colours on those cards.

 

[RandomFactoid]

Bit of a sidetrack, but what do people think of the dipsticks that you scan with an app for numbers? I've used ones made by JBL long time ago, pretty sure there are other products now too. Any good?

 

[MichaelJ]

Shame I can’t see the numbers and colours on those cards.

@hypnogogia, My bad- hope this picture below makes more sense to you although its pretty small:

Cheers,
Michael

 

[MichaelJ]

Bit of a sidetrack, but what do people think of the dipsticks that you scan with an app for numbers? I've used ones made by JBL long time ago, pretty sure there are other products now too. Any good?

You mean taking a picture of a dipstick? If so, as an imaging scientist (of sorts) by profession, I would be cautious with something like that unless the light the dipstick is photographed under is very well controlled and meets the apps (correct) assumptions about the response of the imaging sensor/device. Maybe I am just being a contrarian because its something I know a bit about, but it sounds like a gimmick to me - just like those apps that claims to be able to measure your photosynthetically active radiation (PAR) in your aquarium.

Cheers,
Michael

 

[hypnogogia]

@hypnogogia, My bad- hope this picture below makes more sense to you although its pretty small:

View attachment 200185

Cheers,
Michael

Interesting. The bottom two seem to be reversed (unless it's the colour rendition on my monitor). Thanks

 

[hypnogogia]

Bit of a sidetrack, but what do people think of the dipsticks that you scan with an app for numbers? I've used ones made by JBL long time ago, pretty sure there are other products now too. Any good?

I used those for a while and found they were not reliable in that it consistently gave more inflated readings than using liquid tests. Ive now given up testing all together as I found it adds no value to what I do, other than the occasional Gh, Kh, and pH test.

 

[RandomFactoid]

You mean taking a picture of a dipstick? If so, as an imaging scientist I would be cautious with something like that unless the light the dipstick is photographed under is very well controlled and meets the apps (correct) assumptions about the response of the imaging sensor/device. It sounds like a gimmick to me - just like those apps that claims to be able to measure your photosynthetically active radiation in your aquarium.

Cheers,
Michael

Kits like this:

ProScan Water Test Kit

The JBL ProScan Water Test Kit brings forward a new generation of water analysis using your smartphone. ProScan is fast and precise with results displayed as numbers and results evaluated with a good, medium or poor scoring. The App may also provide recommendations for optimal water quality...

www.pond-planet.co.uk

 

[MichaelJ]

Interesting. The bottom two seem to be reversed (unless it's the colour rendition on my monitor). Thanks

Hi @hypnogogia, I have the chart on hand here and took the picture below. Its distinctly different when I look at it with my eyes under light that correlates with ~5000K.

However when I measure the L* (The CIE perceptual lightness from a standard observer) value on the 4.0 and 8.0 patch on the Saltwater chart they read almost identical - but as far as chroma and hue goes you can tell... but under slightly different light due to metamerism (perceived identical colors but distinctly different spectral distribution) it might be impossible to tell... Anyway, it just goes to show how tricky this can be even for humans to interpret - let alone a software application - when matching the color of a liquid up against these charts.

Cheers,
Michael