I can't pm you
@Walilamdzi for some reason.
Anyway, I did the aquarium test using 2 reagent bottles as shown above. SN is bought from a polish seller selling it inside two ziplock bags.
Used two 1l bottles of distilled water for each test and shook both bottles to let SN dissolve.
For a first test, I aimed for the 2mg/l solution. Squirted away about 1ml (close to 1.3ml because there were some air bubbles inside a syringe) of water from a second bottle. Weighed 2g of SN and poured into a first bottle. Forgot to squirt 1ml from a first to second bottle and wasted 5ml of water. The amount is so small that it didn't affect results at all. Squirted 1ml from a first bottle into a second one and measured its content.
2000mg / 995ml ~ 2.01mg/ml, so the result is ~ 2.01mg/l.
View attachment 38503
For a second test, everything went perfectly. Aimed for the 5mg/l solution. Squirted away 1ml of water from a second bottle. Weighed 5g of SN and poured into a first bottle. Squirted 1ml from a first bottle into a second one and measured its content.
5000mg / 1000ml = 5mg/ml, so the result is 5mg/l.
View attachment 38504
The darker spot inside is due to a camera angle, so it gives a shadow. Look at the brighter spot.
Three other members also tested this SN using the aquarium test and said the results were perfect.