Water treatment tabs-which is best?

I tried the Aqua Mira drops and didn't like having to count the drops, mixing, etc. The tabs are so much easier. I use the MRS tabs with 0.70 liter smart water bottles. I easily break the tabs in half and use that per bottle. I carry a small ziplock bag, say 2" x 2" for the half's in the event I don't use them.

nm

Of the four brands you listed, three of them (Katadyn, Potable Aqua, and Aquamira) are indeed chlorine dioxide, same strength, similar foil packaging, and probably are all made by the same German-based company. When that factory was destroyed in a fire in 2013, the three brands soon became "out of stock." At the time, I contacted each of the companies about when their ClO2 tablets would be available, and each company told me "Our source factory burned down, so we have to wait until they rebuild their facility."

MSR's Aquatabs, on the other hand, are sodium dichloroisocyanurate, whatever that might be. As for MSR's claim that one of their tabs treats 2 liters of water, this seems a bit unclear to me. They say that one tab can be used with 2 liters of "treated" water, and one tab for 1 liter of "untreated" water. Maybe this refers to municipal water in a developing country, which has purportedly been "treated" by the authorities, but is still rather suspect?

I've not tried MSR's tabs, but I've use all 3 of the chlorine dioxide brands. Those all seem identical, other than the occasional price differences.

Apparently I am the one who is confused.

Looking into chemistry now …

Nope, Greg–I'M the one that's confused! Thanks for your last (edited) post, as it had me going downstairs to check my water purification tabs.

So both my Potable Aqua chlorine dioxide tablets and the Micropur MP1 tabs list identical active ingredients, same percentages (I haven't any AM ClO2 tabs, but I bet they're the same):

Sodium chlorite: 6.4%
Sodium dichloroisocyanurate: 1.0%

So do these two chemicals combine to create chlorine dioxide? I think that sodium dichloroisocyanurate by itself simply releases free chlorine upon contact with water, and this chemical has been used overseas for quite some time. It's fairly new in the States, but W.H.O. and other international agencies have been employing it for years.

We need an inorganic chemist to help clear this up for us, Greg…

I'm not a chemist, and apparently am not reading very carefully. I missed the dihydrate component listed on the chlorine dioxide labels. However, I think it goes like this –

Sodium Dichloroisocyanurate by itself generates "free chlorine"

Sodium Chlorite + Sodium Dichloroisocyanurate Dihydrate –> Chlorine Dioxide

"Chlorine dioxide is a neutral chlorine compound. It is very different from elementary chlorine, both in its chemical structure and in its behavior.[4] One of the most important qualities of chlorine dioxide is its high water solubility, especially in cold water. Chlorine dioxide does not hydrolyze when it enters water; it remains a dissolved gas in solution. Chlorine dioxide is approximately 10 times more soluble in water than chlorine." (Wiki)

Good work, Greg. I too missed that DIHYDRATE bit, but I'm not sure it matters.

"Sodium Chlorite + Sodium Dichloroisocyanurate Dihydrate –> Chlorine Dioxide"

Actually, –> Chlorine Dioxide + Sodium Cyanurate (which is apparently harmless and is excreted by the body very rapidly).

While the sodium dichloroisocyanurate will release free chlorine on it own when placed in water (which is how MSR's tablets kill cooties), it also is the source of chlorine that sodium chlorite requires to form chlorine dioxide (which is what the other 3 brands are, and that's why they include NaDCC in their formulas).

I think we've done it, Greg, not that anyone really cares but the two of us. Still, the truth is out there, and the Colorado boys need to know.

So does the OP.

MSR, being free chlorine based, doesn't wack crypto.

And, Potable Aqua does come Iodine based as well. Bottles look the same.

And, there are "AquaTabs" from none of the above.

And, "free chlorine" is more sensitive to temperature, turbidity and water pH.

Due diligence and all of that.

So the MSR tabs are inferior to the chlorine dioxide triplets as they don't kill crypto at all and don't work as well in cold water, correct?

All chlorine dioxide tabs are the same (same factory, same packaging, etc) so the only variable is price.

Thanks for your help