Method SN aquarium purity testing

[TurboCharcha]

Ok i think i finally get it now (kinda). Allthough the color of square under 5 is like color of wet sponge, would be hard to tell the difference between 1 and 5 no? Anyway gotta buy all the stuff and tested it again. I will still post somewhere on the forum my results, cuz i'm always not sure about anything. Thank you!

Yes, it is indeed hard to tell the difference, that's why strip and reagent tests are considered approximate tests. I don't have any problem answering more of your doubts if you have any more.

 

[Y444]

Yes, it is indeed hard to tell the difference, that's why strip and reagent tests are considered approximate tests. I don't have any problem answering more of your doubts if you have any more.

Upd
I gave up. I don't know how can you measure everything so accurately. I bought 2 bottles of distilled water, but when I poured them into a measuring cap, it turned out that both bottles had different volumes of water and, of course, not precisely 1 liter. I tried to get some regular tap water, but then I realized that it was unrealistic to measure 1 liter of water with an accuracy of a milliliter. Even if i use a syringe and measure 1l of water in milliliters, i will still most likely be wrong by atleast 1-2 milliliters but probably way more.

 

[TurboCharcha]

Yes, you will be off by some amount, always. The most accurate way (that I know of) to fill a container up to certain volume is using a volumetric flask. If you have the money, I would suggest buying two 1L flasks. You will probably need a funnel too to pour the water into it. Also, Pasteur pipettes are inaccurate. The best pipettes to transfer a small volume you can use are volumetric pipettes (which measure a single volume). Both of these implements, volumetric flasks and volumetric pipettes, are made specifically for situations in which volume accuracy is paramount. Note that pipettes are sold separately to the pump or pipette filler you need to use them. There are many types of pumps. In a pinch, you can use a simple ear cleaner like this one to fill the pipette.

Having said all this, even if you finely control the mass of SN and the volumes of solution to make a solution with your desired concentration, you will have a hard time telling the exact color of the test strip or reagent test. The ways there are to measure the resulting concentration accurately are way more expensive. The way I know is to use a spectrophotometer to measure the light wavelengths reflected by the SN solution after the Greiss Reagent (what gives the red hue to the SN solution) is added. Spectrophotometers are very expensive.

What I would do if a spectrophotometer is out of the picture, is buy more than one brand of strips and reagent kits and test them all with the same solution, then I would repeat the test with other target concentrations. The volumetric flask and volumetric pipettes suggestion still stands, there are plenty of videos on the internet that teach you how to use these tools.

One last thing. When you transfer volumes with a pipette (regardless of the type), you should do it before adding water to dilute it to the desired volume. Transferring the volume to an already "to volume" water container would make the solution more diluted. I see lots of instructions on this site that don't take this into account. Also, make sure your implements are dry and clean before use.

 

[aiyuxhan]

link to the test strips please? :(