Distilled Water and Filters

Found Contributor.

Monte Montana said:

I’ve posted this before, but I guess it bears repeating:  When you finish a trip and get home, use DISTILLED water to clean your BeFree.  Put about 8 oz in your bottle, swish it and shake it, then squeeze it through.  Repeat.  This will clear out all the mineral deposits that cause clogging when it dries out and yer good to go!

When you finish a trip and get home, use DISTILLED water to clean your [filter] ..

Uh oh.  Time to clean …. or time for another trip.

Oh you mean like my shower head? What if you rinse your filter with diluted CLR?

Daryl (and Daryl), after flushing with distilled did you store the filters wet or dry?

JR

I always store the filters dry.  I typically shake them out and then twirl them on the end of a cord.  I then let them dry hanging from a cord in a sunny window.

Diane,

What’s CLR?

calcium lime rust?

a commercially available product for dissolving deposits from water filters

it can also be used for other applications like plumbing

Would rather drink arsenic, but have used CLR to soften lime rust so it can be scraped away.  To avoid all this, just pick up a new Sawyer Mini at W-Mart before each backpacking trip.  For multi week trips, a new Mini goes into the food caches.

Found the CLR at a local dollar store.

I missed that other thread. Thanks for the tip.

Just to clarify, do you run the distilled water through the filter along with a small amount of bleach as Sawyer recommends before storage or do you only use the distilled water by itself and let it dry?

More power to you guys, but I wouldn’t use CLR or any other scale removing chemicals to run through my filter. That’s not any better than drinking a glass of water with a little CLR thrown in the next time you use it.

Lab testing is $$$… up to a few thousand dollars per sample, depending on the test. I doubt Sawyer or other manufacturers have done extensive testing with unorthodox chemicals not typically found in water.

Generally, tap water has a pH up to 8.5 and is slightly basic to prevent pipe corrosion, while distilled water is slightly acidic (< pH 7). But I doubt distilled water is acidic enough to remove scale deposits. Rather, I’d say it just serves to flush out the water with the hardness in it.

I’d be curious to know how flushing with diluted distilled vinegar would affect filter membranes. Some filters can be ruined by high pH chemicals (like bleach), and some by low pH (vinegar and other acids). Anyone tried vinegar? It’s serve to both disinfect and remove scale deposits (probably with a short soak).

We do lots of irrigation water analysis here, which includes tap water from many locations. pH, hardness (Ca and Mg), and  TDS (Total dissolved solids; convertible to EC  (electrical conductivity) will vary immensely by location. Humid regions will general have good quality water with a pH less than 7. Arid regions are problematic with lots of dissolved minerals (salts), and bicarbonates.

Using distilled water (pH of 7.0) sounds good to me, especially since I live in arid Central California. Using rain water might be even better, it generally has a pH of 5.5 and is salt free.

If you use ground water or even lake water like Lake Michigan,   the chances of the hardness of your water is above normal limits and will create issues with the filter if the the filter material dries in storage.

Robert,

My old method was to use tap water plus bleach prior to storage.  With my successful testing of Monte’s distilled water suggestion I will now use only distilled water and bleach prior to storage.

Seattle Tap Water

Calcium: 17.0 ppm
Sulfate: 2.0 ppm
Magnesium: 1.0 ppm
Chloride: 4.0 ppm
Sodium: 4.0 ppm
Bicarbonate: 18.0 ppm
PH: 7.8​

Found this on the interweb.

Is it possible to ever evaporate the water out of the hollow tubes in the filter?  They’re pretty small inside diameter so I would think they’ll stay wet forever.  Water won’t centrifuge out of them.

Unless you go to extremes like putting in an oven, spinning in fast centrifuge.  But why would you want to?

I always spin the filter at arms length a few times to get all the water out that’s outside the hollow tubes.  Just so it doesn’t drip out inside my pack.  I think it would also prevent damage from freezing.

I just backflush with city water (Portland Bull Run) and call it good.  Haven’t had a problem (knock on wood)

Jerry,

So there is something you and I must be doing differently?  Both my Squeeze and Be Free filters will freeze up after a week of drying.  It will take a couple hours of work with hot water and vinegar to get them going again.

Do you use bleach?  Do you have fluoride?  Do you dry your filter in a sunny window?

“Unless you go to extremes like putting in an oven, spinning in fast centrifuge.  But why would you want to?”  Well I wouldn’t do either of these things.  But it seems that storing a damp  filter for, say, 9 months is asking for bacteria growth.  You backpack more often than I do.  I’m a May-Oct backpacker.  Perhaps this protects you from bacteria build -up?

If you send me, say, 10  gallons of Portland water I’ll try some side to side comparisons with Seattle water.

Okay, 10 gallons of water going your way (not) : )

I haven’t used the squeeze for a month.  I backflushed it with Portland water, shook water out vigorously, stored in plastic bag for a month.  Just got it out, works no problem.  Shook it out and put it back in bag for next trip.

There are bacteria all over.  Fungi.  viruses.  mold…  Don’t worry about them.  It’s good for your immune system to experience them frequently.  I wouldn’t recommend covid though : )

When I first use the filter I’ll flush a cup of water through just to clear it out a bit.

On my last trip, in the Trinity Alps, I was drinking alpine water so I didn’t bother treating it, so the filter has been sitting in it’s bag for longer than normal.

I never put bleach in it.

The inside of the filter is not a good environment for micro organisms.  No light.  Very little nutrients.

We do not have fluoride in Portland.  I got a letter a while ago, from the water department, apologizing because they previously erroneously said there was fluoride in the water.

To me, that’s stupid to put fluoride in drinking water.  They shouldn’t be putting nutrients in drinking water.  What they put in is impure fluoride that includes unhealthful minerals like arsenic.  It’s all small enough quantity it’s probably not unhealthful, but it would be better to make sure everyone can go to the dentist regularly, use fluoride toothpaste.  Fluoride in drinking water also goes to washing clothes, flushing toilet, irrigation,…  But I don’t have a lot of passion about this one way or the other.

This is chaff isn’t it?

LOL. Shipping water = not cheap :) Trust me… had to ship a few 5 gallon jugs to a lab for work one time.

I doubt bleach, or fluoride in the water, causes any issues with seizing. I haven’t ever had mine lock up after storing, and we have what’s considered hard water, but Daryl you’ve probably got a lot more use on your filter than I have. I’m no where near that 100,00 gallon mark. Daryl those numbers seem low. Looks like pretty darn soft water (low hardness).

Also, another issue with excess biological material (bacteria, algae, etc.) can cause fouling of membranes. Water treatment plants have a lot of different ways to mitigate that, but still something to consider. One way to do this in RO systems is to prevent it being exposed to air, or deoxygenate it, prior to running it through the process Jerry, I’d be curious to see inside your filter if you broke one open and popped it under a microscope! Not all microorganisms need light, but they do need a food source of some kind. Else they be skinny microbes.

Interesting note… Sawyer makes what they call their PointZeroTwo system. It actually is a nanofilter with a max pore size of 0.02 microns (basically one level below RO in terms of removal efficiency/”pore size”). It removes a lot of stuff, to overgeneralize, and is likely overkill and impractical for backpacking, but neat nonetheless. I reached out to Sawyer and they mentioned they mostly use it for medical purposes (i.e. providing clean water where it’s not available). It’s 4.75 oz for the filter, but you need high head (to elevate the dirty water way above the filter). Also much slower than the Mini or Squeeze, of course.

I recant what I said in my other post about not seeing any nanofilters available…now I have.

does azure blue dye have a particle size somewhat larger than 0.1 microns?

could you use that to see if your filter is working? Put it in water.  Run through filter.  If the output is blue then your filter doesn’t work.

I saw some on amazon, except I think it’s mostly acrylic – not what I want.  I saw some powder but it’s $100 – not what I want

The biggest problem with hollow fiber filters is you can’t freeze them (if you can get past the clogging problem).  But the hollow fibers expand a little when you backflush, so it seems like they would tolerate freezing.  If you can just shake the water out of the outside of the hollow fibers, inside the housing, then the filter should tolerate freezing.  That’s my theory.

Now if I could test a filter with blue azure dye, then I could try freezing it and see if it still works

I don’t want to even think about what my filter looks like inside, it’s probably disgusting, out of sight, out of mind : )

I had luck with CLR but after it didn’t pass the “blow” test BeFree outlines.   It was a last ditch attempt to restore flow.  I have since rinsed with 2L of a mild bleach solution and cleaning with distilled water in a ultrasonic cleaner before storing.  This has worked for the past three trips but I test before leaving and have a new filter in my gear box just in case I can’t revive the old one.

The blue dye was one of the things I asked Sawyer about. I may or may not have reached out to see if they’d provide a few filters for some home experiments (not affiliated with or on behalf of BPL), and planned to post in our previous discussion. I didn’t want to spend $100+ on Sawyers :) But yeah, they said no, but did give some fairly scientific feedback, which is reassuring for a product user of something directly related to public health.

My goal was to test four Sawyer minis for in the following ways, mainly to analyze effects of freezing:

1. Control: Test one with just the blue dye to see removal. As I mentioned before, I don’t have to a lab-grade colorimeter, and probably wouldn’t buy a cheap handheld one either.
2. No water, frozen and thawed: Freeze filter that was brand new out of the pack and dry. Then thaw it completely. Then test with the dye as in #1 above.
3. Use filter, flush with water, then freeze and thaw it. Same as #2 above, but with water still inside.
4. Use filter, then shake it out as much as possible, and gently attempt to purge as much of the water as I could using the plunger. Then freeze, thaw, and test it with the dye.

Some of Sawyer’s comments/issues included, and my overall thoughts/workarounds.

• Sample size was too small to provide any usable data.
  • Agreed, but I wasn’t planning on doing any statistical analysis though… I hate stats problems.
• The blue dye will likely get absorbed at first and then come out in the water later. Also, it wouldn’t mimic any biological material or serve as an indicator, and lab testing would be needed for each of the samples.
  • Won’t know until you try! :)
• Results wouldn’t be citable.
  • Not my goal anyway.

I’m sure they’ve done plenty of testing. But as you mentioned Jerry, the idea was for the dye to be a field test (although chemical treatment drops or tabs is probably just as heavy). They did provide me a handout, albeit promotional in nature, but still informative overall:  https://sawyer.com/wp-content/uploads/2020/02/Sawyer-High-Performance-Filters.pdf

So if anyone has a few Sawyer’s lying around and wants to give it a go, by all means!

That’s pretty much the experiment I was thinking of.  And Sawyer’s comments are reasonable.

I don’t think freeze survivability is something they care about.  They have a successful product with the advice not to let it freeze.  Most users are fine with that.

It would be too difficult to scientifically show that it survives freezing, as per their comments

If they said it survives freezing, some users would not shake the water out sufficiently and the filter would be damaged

I’ve used my Squeeze for years.  I always shake it out.  I try to not let it freeze but there are a couple times where it probably froze.  Even if it’s freezing outside, it takes a while for the cold to “get inside” the filter.  I store it inside a bag.  I’ve seen ice crystals on the bag but water drops in the filter.  It passes the “blow test” but that’s subjective.

I think this is one of those puzzles without a solution.

Here are some facts concerning my water in Grand Haven, MI and why I had issues with my filters UNTIL I started to use distilled water in the cleaning for storage process,  AND now I place the processed clean filter in a sealed plastic bag to reduce evaporation.

My House Water (groundwater) –  43 grains/gal  /  738 mg/L

Lake Mi Water  – 9.5 grains/gal /  160 mg/L  (This changes in the Winter Months even harder.)

Water Hardness Criteria  (USGS)

61 to 120 mg/L as moderately hard

121 to 180 mg/L as hard

more than 180 mg/L as very hard