The main issue here is I am not convinced that one mag rod in vinegar will generate enough hydrogen to yield a satisfying hydrogen concentration, you really need to test that with H2 blue.
Yes, I wish I had some H2Blue drops (unfortunately I found out that shipping H2Blue to the UK costs $85, plus the $30 cost of the product, because it contains ethanol, and apparently this cannot be sent by regular mail, due to regulations, so needs to be sent by expensive courier).
In fact, because I already had some methylene blue at home, I tried to make my own H2Blue drops. This is not difficult to do.
To make 10 ml of H2Blue-type drops, you use the following formula: simply add 30 mg of methylene blue to 9,890 mg of ethanol, and then add 80 mg of colloidal platinum liquid (colloidal platinum liquid can be bought as a health supplement, for around $20). The colloidal platinum is just a catalyst: it allows the hydrogen in the water to react with the methylene blue, and thereby neutralize the methylene blue color. This formula for these drops is detailed in this study (see "Methods/Design" section).
Then you add these drops one by one to 20 ml of the hydrogen rich water that you want to test, continuing to add the drops until the hydrogen rich water stops neutralizing the blue color of the drops (as shown in @streamlover's video at timecode 13:25). Then the concentration is given by: H2 ppm concentration = number of drops X 0.03. So for example, if after exactly 24 drops, the blue color of the drops is no longer neutralized by the hydrogen water, then your H2 concentration in that water would be 24 x 0.03 = 0.72 ppm.
However, when I made up my own H2Blue-type drops using the formula from the study, they did not seem to work: the blue color of even the very first drop was not neutralized by my hydrogen rich water. This failure can either be because my hydrogen rich water is duff, and in does not contain any dissolved hydrogen; or perhaps because the colloidal platinum I bought is duff (I bought it from a small obscure company in the UK).
I wish I had some H2Blue drops, as at least then I could check to see if my hydrogen rich water is duff or not.
Regarding whether just one magnesium rod is sufficient: as far as I can see, I don't think the number of rods will make any difference. It is the amount of acid that you place in the test tube that is the limiting factor. Like @streamlover, I was using around 1.5 grams of citric acid powder, or malic acid power (I also used vinegar). Once this 1.5 grams of citric acid completely reacts with the magnesium rod, the reaction stops, and no more hydrogen is made. But there is plenty of magnesium left on the rod, and if I add more citric acid to the test tube, the reaction starts up again. So it is the amount of acid you add to the test tube that determines how long the reaction goes on for, and much hydrogen is created.
However, without being able to test the H2 concentrations using H2Blue drops, I cannot really know what type of H2 concentrations I am producing using this method.
What does concern me is the following statement in the study that details how to use the "test tube within a bottle" method:
"During the reaction, the H2 gas reduced the height of the water level in the standing bottle, which was gradually pressurized to approximately 4.5 atmospheric pressures by the gas after 24 h at room temperature. After the reaction was terminated, the H2 gas was dissolved by shaking the bottle for about 30 s."
So the study says that as the hydrogen gas is produced, it accumulates at the top of the bottle (see the picture Fig 1d in that study), thereby pushing the water level in the bottle down a bit. The study then says that this H2 gas at the top of the bottle was dissolved by shaking the bottle for about 30 seconds.
I was also getting the H2 gas accumulating at the top of my bottle, pushing the water level down by a couple of centimeters, similar to the picture Fig 1d shown in the study. But shaking my bottle did not cause any of this hydrogen gas to dissolve in the water. I shook the bottle a lot, but the same volume of H2 gas always remained at the top of the bottle. So I am not sure how the authors of the study got their H2 gas to dissolve into the water just by shaking the bottle.
Maybe they used more of the reagents, thereby producing more hydrogen, and thereby increasing the pressure inside their bottle. Increased pressure might then make the gas more soluble on shaking. At the moment, I have no means to measure the pressure inside my bottle (but I might buy a cheap car pressure gauge on eBay for this purpose).
In the study, they say the pressure in their bottle was 4.5 atmospheres (= 66 psi).
I am not so sure just a tiny hole is enough to prevent leaching into the drinking water of other undesirable compounds (not of concern if mag rods and malic acid are used like in the video).
I found that provided you keep the bottle and the test tube inside vertical, almost no reagents get into the water. This is because I don't fill the test tube completely (I leave around a 1 cm gap at the top, as you can see in my video, when I fill the test tube with vinegar). So there is not really any way for the reagents to get out.
But if you start shaking the bottle a lot, or turn it upside down, then you do get some of the reagents leaking out of the test tube and into the water. But that is why I use 99.99% magnesium and citric, malic or acetic acid: because this just creates a safe-to-consume magnesium salts.
Edited by Hip, 04 October 2016 - 11:42 PM.