In the era of distrust of governance, it is important to double-check claims, in particular when those pertain to general health and well-being. One branch thereof is the testing of tap water for impurities, such as dangerous chemicals that might have been under-reported or seeped into the water distribution system inconspicuously due to recent accidents. In order to test water purity, expensive devices exist that perform an actual "scientific" job of measuring the various contaminants in scientific or measurable terms such as concentration expressed as parts per volume. Ironically, the downside of such measurements is that even if the exact value is measured with precision, the interpretation might both differ between values as well as being difficult to determine what the actual numeric value represents in the absence of an expert.

A very inexpensive device is shown in the previous image, that does nothing more than use two electrodes to perform electrolysis on the contents of some cups intended to be filled with water, underneath the device. The device is meant to be placed in two containers next to each-other, ideally two transparent containers such as glasses, with both glasses containing water from two different sources. The device is then plugged-in to the mains and the electrodes that stick into the glasses are powered up and electrolysis is performed. The device has a label that contains the following table indicating the interpretation of the colors that might result from the electrolysis:

The device has received a lot of flak for being inappropriate, ranging from the electric architecture of the device and up to its doubtful "scientific" usage. Here are some ideas to dispel the doubts or set the record straight:

• The electric part of the device is truly a disaster and the cable should be replaced by a larger gauge cable because the power drawn by the device will always end up warming the cable. Opening up the device and replacing the cable, as well as checking out the electronics, will be a project in the future.
• In scientific terms, the idea behind the device is to perform a relative comparison between two different results, one for each pair of electrodes, rather than provide a single result that could be interpreted on its own, or, in case of the criticism, be misinterpreted. In other words, the user is meant to compare the two results together and see the relative difference between the two, not to perform a single measurement and then look it up on the label in order to determine how many contaminants the single result contains. In that sense, the user would then measure two different sources of water, in order to determine which one is better but relative to the other and not necessarily "better" in absolute terms. The former usage pattern is a dead-giveaway that results from the fact that the device contains two pairs of electrodes and not a single one.
• There is a little bit of tulip fever going on in the world that affects this device and seems to paddy caked around the planet due to several levels of misunderstandings. Distilled water is safe to drink but also very bland and not in any way nutritive. That being said, there is not really any measure of "good water", except, say, water that does not contain any well-known viruses or deadly bacteria, otherwise "good water" containing (picking something random) "magnesium" or "iron" in decent proportions is actually a very good thing. Some countries pride themselves, as an example, with their iron-rich water, and drinking it in safe proportions is deemed very healthy. In that sense "good water" does not mean distilled water with no minerals and no contaminants. Having said that, this device will more than likely pick up "impurities" that would counter-intuitively not only be safe, but also nutritive. As the previous point on relativity is made, the user would determine which of the two sources is more pure than the other, but "water safety" as an absolute determinant will not be offered by this device.
• Scientific measurements do not offer a clear overview of how "contaminated" the water is in terms of visualization and they would require an expert that is capable of interpreting the results in terms of relativity (ie: to other sources, personal experience, etc.) such that this device provides a perfect visualization with the mention that the results should be interpreted light-heartedly and relative to the two pairs of electrodes rather than as an absolute.

Either way, the debate on "good water" is a gimmick and a scam that is mostly indigenous to fringe-societies such as Iceland or University of Icleand that need to resort to desperate measures ranging from accepting bribes from Romanian pedophiles and up to peddling snake-oil "volcanic water", in order to fund their need to flex at each other by driving Teslas, that carries no intrinsic nor scientific value except one that would be based on belief and/or opinion. As follows, is the water good because it is pure and close to being distilled, or is the water good because it contains nutrients? Whenever you hear some backwater thumping their chest on the topic of "our water is better than yours", scientifically speaking, you should turn around at 180 degrees and walk straight away from the claimant perpendicular to them before you are made other pseudo-scientific follow-up offers that you cannot refuse.

The base-case consists in placing the electrodes of this device into one or two glasses of distilled water, powering the device on and waiting up to 60 seconds, after which the water should be entirely transparent. In that sense, performing electrolysis on distilled water, will not color the water in any shape or form. This is one degree of relativity, in the sense that any follow-up measurements could be compared relative to the perfectly clear and transparent distilled water (with the note in mind that distilled water does not imply "healthy" nor nutritive).

Here are a few measurements performed, all of them hinging on the relative results between each other and are also very good examples why this device can offer faster results and a better visualization than terse measurements if relative results are considered.

There are two levels of relativity being considered here:

• relative to the base-case that consists in distilled water that will be transparent even after electrolysis,
• the more useful and intuitively intended usage consisting in the relative difference between the results produced by the two pairs of electrodes

The first level is used only weakly and needs one additional source within the same set for the comparison to be valid whilst the second level is immediately observable from the testing itself given a comparison of two elements within the same set.

The Aquaphor Modern 2 is an in-line water purifier that connects directly to the tap and adds an additional tap in order to be able to commute between the tap water and water filtered through the Aquaphor water purifier.

Interestingly, the Aquaphor Modern 2 produces instant results, such that passing the water through the Aquaphor water purifier or obtaining it directly through the tap carries the same time delay. In other words, it seems barely likely that the Aquaphor Modern 2 would have had time to actually filter the water when the water being dispensed passes at the same speed through the filter as it does from the tap.

The results seem to speak for themselves, and the Aquaphor Modern 2 seems a total waste of money and time. The manual of the device is even "cheekily" worded, with the manual stating that the "Aquaphor Modern 2" is meant to purify "drinkable water", and if the water was originally drinkable, it is not so clear why it should be purified further. In any case, the Aquaphor Modern 2 will not be able to clear up non-drinkable water, even from its own manual and statements of the creators.

To complement the previous result, this is a comparison between the Aquaphor Modern 2 and an Aquaphor Kettle filter. The Aquaphor pitcher is a simpler and less expensive device that requires the user to put water at the top, wait for the water to be filtered going down through a filter and then to collect the water from the pitcher simply by pouring the water out.

The counter-intuitive observed results could be due to the fact that the more expensive Aquaphor Modern 2 offers the water directly whereas the pitcher requires the water to seep through a filter, thereby taking some time to be filtered, such that the cheaper pitcher is a solution that provides much better results.

This test is between the Aquaphor Modern 2 (no better than tap water) on the left and bottled carbonated sparkling water on the right and more than likely a test that should be discarded. An interpretation for the carbonated water coming up blueish-greenish could be due to ulterior reactions during the electrolysis due to the carbon-dioxide () contained within the water. Again, we have to bear in mind that the relative difference is to be sought such that comparing two carbontated water sources or two flat water sources together as distinct pairs might offer results easier to interpret within the pair itself. In other words, compare only carbonated with carbonated water and flat water only with flat water.

In the absence of any control (ie: carbonated water from a different source) there is not even a point in naming the bottled water brand that leads to the blue-green result after electrolysis.

Lastly, this reaches back to the point about "good water", and it is perfectly valid that water with lots of minerals is, in fact, the better water rather than pure distilled water. However, if you're out in the wilderness (and just happen to have a or socket in the wilderness with you) and performing this test, then clearly not drinking the blue-green resulting water is a safer policy.

As a one-step up from distilled water, here is a comparison between boiled water and tap water. Note that the water has been boiled inside a metal container such that the "greenish" aspect might just be due to traces of metal from the metal drum that water was boiled in detaching from the walls and mixing with the water - even so, these are truly traces so it seems plausible that the boiled water is much better than the tap water relatively.

Even explained using physics instead of chemistry, distilling is a superior operation compared to boiling, that ensures that any "heavy" materials that do not transition to a gaseous form at which is very little in the chemistry world, with, as an example, iron evaporating at , are left behind after water becomes a gas. Boiling however is not that bad of a tradeoff because boiling would completely destroy organic contaminants such as viruses and bacteria that all cannot cope with the water boiling point at .

The conclusion is straightforward; if you do not have distilled water, or lack the capability to distill, then just boil the water for a few minutes because it will purify the water much more than any expensive water purifier would. If you want to go the whole mile, just use some lightly radioactive carbon to pass the water though it, similar to the pitcher, although, that is clearly overkill.