I checked the MSR website but it didn't give weights/volumes of any of the reactants. Can you give me an approximate amount of the salt used (tic-tac size, sugar packet size?) and do you dump the original 2-3mL of water into your water to be treated or just a few drops of the MIOX solution? I'm trying to reverse-engineer this thing. $100 is a bit steep for my pocketbook, but a 9-volt battery and two pencils I can handle.

Thanks.
-Blast

Hi

According to my instruction booklet the reaction chamber holds about 1ml of water.

Once it's full, you shake it 10 times to create a dilute brine from the rock salt which is held in another chamber above the reaction chamber. The chamber holds about four lumps of rock salt about the size of a tic-tac each. This is not the most accurate measurement but when you subsequently hit the button to activate the unit, it will let you know if the brine solution is too weak. I assume it does this electronically, by measuring the resistance of the solution.

According to the booklet the unit ships with 45g of rock salt which comes in the little bag provided and this is enough to treat about 200 liters of water.

The tricky part is the reaction time. The unit is designed to run for four different lengths of time and produce different concentrations of chlorox to treat 0.5, 1, 2 or 4 litres of water.

One click (0.5 l) and it runs for 5 seconds, two clicks (1 l) is 10 seconds. I tried four clicks (4 l) and it ran for about a minute.

The batteries it uses are CR123's in series, adding up to 6v.

It comes with 50 test strips.

I'm guessing that it should be a near-saturated solution. The concentration could be determined by the MIOX unit by measuring the conductivity of the solution ie by measuring the current flow.

Reaction time could be determined experimentally by using test strips just like you do to verify the MIOX results.

On the other hand, there's no way to determine if you're producing the "mystery ions" as the MIOX people claim that they can't detect them either. I think there's some voodoo going on there. Electrolysis of NaCl should be very well understood by now.

Hey Blast, Same here... it's a bit pricey for me to justify (but who knows). But more importantly, it would be valuable to know the field expedient measurements to use simply because I can think of a lot of situations where you wouldn't have this, but maybe you have a pencil or two, some wire, and a 9 volt from a toy in a car, etc.

I wish I still had access to a lab... wouldn't take too long to figure out the amount of salt and time @ voltage to react what you need. Hopefully someone here has the equipment to calculate it (I haven't been in a chem lab in 10 years! - I'd have to brush the dust off of the corner of my brain that understood this at one point) <img src="/images/graemlins/smile.gif" alt="" />

It could be that the electrodes themselves are giving off ions (like Cu). That's likely why they are using carbon graphite from the pencils instead of dipping wire directly into the solution.

According to the MSR website the MIOX unit uses platinum electrodes for both the anode and cathode. These shouldn't release any ions under these conditions whereas the carbon/graphite *might* drop something off the anode. I'm not worried about toxicity but I am concerned about the carbon anode creating different oxidative products.

Hmm, 1 mL of a saturated NaCl solution, 6V DC, I need to look up the current put out by the three batteries. I wonder if a chlorine test kit for a pool would be able to help me measure the resulting chlorine strengths...

This could be a fun weekend. Note to self, review first aid for chlorine gas inhalation with Kuovonne...

-Blast

<img src="/images/graemlins/smile.gif" alt="" /> Make sure you do this outside! Chlorine gas is rather nasty.

For more in depth discussion I found this site:
http://stuff.silverorange.com/archives/2004/september/msrmioxpurifier

Read the posts, especially responses by Katie Bolek from MIOX to many of the same questions and concerns posted here.

From the same article, Ms. Bolek mentions:


So, that should help set the foundation for some of the reactant quantities. Next question... are they using the straight 6 volts?

Blast, their rep mentions "A more "typical" shaking of the purifier will generate a brine concentration ranging between 60 and 80 g/L" That sounds like the base concentration and then the electrodes run power through them until the set dosage/concentration is sensed. They mention it is not time based because the amount of shaking changes the NaCL concentration and thus both the current resistance and the amount of salt available for reaction.

Perhaps it measures initial resistance and calculates the "low salt" message from that... Once it gets above it's threshold, it fires up, and based on dosage, probably just stops when the resistance changes by a certain percentage. Perhaps a multimeter would be helpful in this rig to get a good idea of the time/concentration ratio needed for a given volume of untreated water.