11

Exclude reasons one by one Surface biological contamination: use two vessels, wipe the one of them with H2O2, hydrogen peroxide solution, leave another untreated. Check if time till smell appears is different by a few days. Bacterias can survive 20% vinegar and 100*C for a short time, some of them, if they are in a sleeping stage, it is not quite reliable ...


6

As suggested in the comments, the predecessor of the method that uses "Missouri" tablets was developed at the University of Missouri (Columbia, Missouri, USA). I believe the first report was from 1972 and named the method as the "Missouri Automated Nitrogen Method (MANM)". They also refer to it as the "Missouri Technicon" method ...


4

A few more thoughts: fresh water taste is AFAIK associated with come $\ce{CO_2}$ being dissolved in the water. This can get lost, and make the water taste stale. Here's an easy experiment to check this: compare the taste of: fresh tap water, water gone stale "your way" (cooled to the temp of the fresh tap water), and de-gassed fresh tap water: ...


3

Most drinking water has residue like what you are showing. Boiling water shows there are ions in the water, but it does not show what kind of ions are present. Boiling water is practically useless when determining scaling potential and it is not safe to do using cooking pots and pans. Part of the reason laboratory equipment is more expensive than cooking ...


3

Another possibility is the grease spot photometer (aka Bunsen photometer) German Wiki page. This can be homemade, you need a piece of paper, some wax or oil, two light sources, a meter stick and for the measurement of solutions also some e.g. cardboard to shield unwanted light. Also the darker the room, the better. The underlying idea is that light ...


2

Russian interstate standard GOST 18293-72 "Drinking water. Methods for determination of lead, zinc and silver content" (PDF in Russian) suggests to use sulfarsazene (plumbone), which forms orange-yellow complex with lead(II). Reported method sensitivity (spectrophotometry): $\pu{0.5 μg L-1}.$ A brief review in English [1, p. 315]: To determine lead in ...


2

Google is your friend. Using "Calcium chloride solubility", you find plenty of references where this solubility is given at different temperatures. Expressed in grams $\ce{CaCl2}$ in $100$ mL water, it is $59.5$ à $0°$C, $64.7$ at $10°$C, $100$ at $20°$C, $128$ at $30°$C, $137$ at $50°$C, $147$ at $70°$C, and $159$ at $90°$C. Do the same with Magnesium ...


2

Definition of hardness per a source: The simple definition of water hardness is the amount of dissolved calcium and magnesium in the water. Hard water is high in dissolved minerals, largely calcium and magnesium. You may have felt the effects of hard water, literally, the last time you washed your hands. Adding $\ce{Na2CO3}$ introduces the carbonate ions: $...


2

I also find the smell of chlorine bleach smell annoying and have developed a rapid way to safely remove the smell, likely with more disinfecting and odor removing benefits. Start by placing dilute hydrogen peroxide in a spray bottle. Proceed to apply to the areas that were the subject of a bleach application. Spray also into the air. Interestingly, in a few ...


1

It appears to be safe, provided that you are putting it into one of the delivery systems that it’s made for which I found through the link you provided. Here is one of the delivery systems: https://www.pineco.com/eng/products/dosing/polyphosphate-dosers/spillo-polyphosphates-doser-dm Per the specs, it delivers 3ppm, which means that you’re only introducing ...


1

It is possible that the ability to release soluble copper ions could be reduced with age. I am assuming, for example, that a very small amount of the cuprous oxide coating could react with, say, carbonic or hypochlorous acid (from chlorinated water) to create a poorly soluble basic salt. However, with time, to quote a source, namely Handbook of Industrial ...


1

In my supported opinion, it’s first chemistry (actually Fenton-type chemistry and contributing photocatalytic sunlight ). I am assuming one has copper (or iron) metal pipes bringing in the water containing dissolved oxygen into their home. Further, it has been treated with say Chlorine (creating residual Hypochlorous acid, HOCl) or even Chlorine dioxide (...


1

The solution gets warmer by diluting with extra water, but no violent reaction. I suggest to do a test, if the temperature raise is concerning you, e.g. because of the tubing temperature resistance. What can also be done is applying solution with graduating concentration, so warming would be spreaded in sevceral steps. But as hydroxide is already quite ...


1

Water passing RO does not have the same chloride concentration. The raw RO water contains almost no ions, aside of those that passed by leakages of the osmotic membrane. This disbalances the water natural $\ce{CO2/HCO3-}$ pH buffer, leaving the ionic alkaline buffer part before membrane, so water becomes more acidic with corrosion aggressive $\ce{CO2(aq)}$.


1

My understanding is that the water in glaciers constitutes over 2/3 of the designated 'freshwater' on earth and is an integral part of the so-called water-cycle. Per U.S. Geological Survey, to quote: Just because water in an ice cap or glacier is not moving does not mean that it does not have a direct effect on other aspects of the water cycle and the ...


1

Water of glacier origin is at the beginning very close to distilled water. As it comes into contact to sedimented dust and rocks/minerals in a glacier, or flowing from it, it gets contaminated by solid particles ( glacier rivers are very turbid ) and eventually by some dissolved minerals. But even then, mineral content is still very low, compared to other ...


1

Take 10 mL of your solution. Add an equal volume of NaOH 1 M. Heat to 100°C and test if the gas has the odor of ammonia. Or check if the gas has a basic reaction by introducing a small and wet indicator paper in the gas getting out of the hot solution (without teaching the glass container). If yes, it means that there is some ammonium salt in the solution. ...


1

Making the solution in a single step is inaccurate up to impossible. Try to find a crystal of lead nitrate with the mass close enough to $\pu{1 mg}$ Try to weight up $\pu{1 mg}$ on scales with good enough accuracy. Try to make such $\pu{1 ppm}$ solution stable enough. The usual thing is to create a concentrated stock solution ( e.g $\pu{1000 ppm}$ and ...


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