you cannot be sure the uv will get in all cracks and crevices, i wouldn’t trust it
Seems like when I was a kid some barber shops used them and they would park their clippers under the lights ?
That commonly cited number for lamps is power consumption, not emitted power, at least as far as I know. In addition a bulb emits light in all directions whereas an LED is highly directional. So surprisingly low power actually reaches the surface from lamps. My informal comparison between 3x7.5mW LEDs and a typical “4W” rockhounding lamp shows about the same, or even maybe a little more mineral fluorescence for the LEDs. Yes, the emitted power is low for UVC LEDs at this time, but it’s what we have to work with.
Klaran LED is always UV Output power not electrical power
Its like claiming my Ford engine from 1969 burns 20 liters driving 100km so it has more Power than a modern Turbo Diesel that burns only 7 liters on 100km
The Klaran LED runs at 8V and 500mA so that’s a solid 4W electrical power, not sure if UV LED or bulb is more efficient on UVC, 365nm LEDs are quite more efficient than Bulbs
Thanks for the link, I can’t quite figure out how to calculate either the time required for disinfection, nor the UV output in mW… can anyone offer any insight?
I’ve an expensive SW mineral lamp which produces a shedload of UV, A mini UVC light would be cool for mineral shows etc.
true but who knows if it worked?
they also used jars of ‘barbicide’, whatever that is.
wle
the MSR guardian blows everything else out of the water.
yes, it's more expensive and larger than something like a sawyer squeeze. but it's SO much faster and easier to use, and it filters down to 0.02u making it basically the safest filter available. the flowrate is a dream (2.5L/min), it automatically backflushes itself (so it doesn't clog) using a portion of the pumped water with every stroke, it's quite durable, it's rebuildable (the replaceable filter cartridge is good for 10kL i think), etc. imo, the size is very easy to justify if you have two or more people. filtering water for a group can add up to a lot of time that should be spent having fun.
seriously, forget everything else and get this thing unless you absolutely cannot carry it because of its size. i've gone on weeks-long backpacking trips with it and was glad to have it. save weight on something else.
To each their own. HYOH (hike your own hike).
While it’s good for you;
- It costs $350, 14x what a sawyer does
- The filter cartridge is rated at 10k liters, and a replacement costs $150. The sawyer is rated at 1MM liters and a new one costs $25.
- At over a pound, it would be fully 20% of the weight I carry on many trips
- While I’m sure it is durable for what it is, all the handles, nipples, springs, hinges, o-rings etc. are all potential failure points either for wear or an accident. The sawyer is just a simple, durable, single piece.
Protozoa are largest, bacteria are medium, and viruses are the smallest. Most filters don’t catch viruses, although to be legally called a water “purifier” the MSR guardian apparently does filter viruses.
In north america, viruses in backcountry water sources are exceedingly rare and of little concern. In other parts of the world they are however.
The smallest concern is heavy metals, and no hollow fiber filter can catch those, generally you use activated charcoal for that.
Isn’t the 99.9% thing too dangerous?
I mean the number gives you confort, but in a puddle of water there are certainly more than 1000 viruses, so at least 1 is bound to get trough, enough for you to die
those are good points, sac02. out of the filters i've used, sawyer squeeze (i think the 'mini' one or whatever?) is my second favorite. it's a cool product, and i still use mine sometimes.
for me personally, the expense is a drop in the bucket compared to taking time off, travel expenses, other gear, etc. but yea, it's way more expensive than other water treatment solutions.
and since you mention failure points... for your consideration:
it's not just one simple, single piece. there's the syringe to back flush it. i haven't had that break on me, but i guess it's possible. i've seen hand cranks on other pumps break, so i guess someone could be rough with a syringe and mis-insert it while distracted and break the plunger. also, the rubber part of the plunger wears out and degrades over time. i've discarded plenty of syringes used for other things due to this. the friction gets so bad that it becomes basically unusable.
there's also the squeeze bags, and i have had brand new ones break on me during just a single trip. i think rolling them up wears them out or something, so be careful how you do it. my friends and i had to help each other pinch shut the small edge leaks in the bags while one of us did the overall squeezing. it was like a 3 man operation every time we needed water. and yes, we had a backup bag. maybe that was just a bad batch? i don't think we were being particularly rough with them, so idk. my solution to this is to bring even more extras and throw the used bags out after each trip.
finally, the sawyer squeeze is damaged by freezing, and it's not necessarily obvious afaik if it's been damaged this way. an insidious failure mode for something so important. the guardian will tolerate freezing.
in my personal experience, not a single failure on the guardian yet, and i've used it more than sawyer at this point (a handful of 1-2 week trips).
sac02's response is perfect. depends on your water source and level of paranoia. i've never personally worried about safety where i drink with sawyer's 0.1u pore size. at least not as far as microbes go.
mostly i love the guardian because of its ease of use and flowrate. such a time saver and a treat to use.
good question. read up on concepts like MOI if you like. it's different for every virus and for every individual (based on factors like your immune system).
http://www.virology.ws/2011/01/13/multiplicity-of-infection/
http://www.virology.ws/2011/01/21/are-all-virus-particles-infectious/
polio can require like 1k virions for good chance of infection. norovirus as few as 10. one particle probably won't do it.
any reduction in virion concentration is a good thing. i'll take what i can get, but you won't catch me personally drinking from water sources likely to contain polio and shit like that. thankfully, that's nowhere (?) in the US.
I put your question into a Google search and found, among the first page of hits, this:
Lord, I feel old. When I was a kid growing up in North Carolina, it was safe to swim in or drink from most any creek in the area. Now? Not so much.
I wonder if any of these filters remove the Teflon chemical family
that’s lasting forever in the ground and groundwater.
depends. whose paranoia are we talking about?
you could distill it also.
Fair point on all costs being relative.
You can leave the syringe and bring the more robust coupler to use your bottle to backflush. It can stay on the filter so low chance of losing a separate piece. Lighter than the syringe too.
Yeah, the Sawyer brand bags are well-known to be garbage. Platypus bladders USED to use the standard 28mm threading, but the jerks changed to proprietary threading. CNOC bladders have standard 28mm threading and have a very good reputation, as does Evernew. You can also use many waterbottles with standard 28mm threading.
I did not know the Guardian will tolerate freezing (In fact I was assuming it would also fail). That is excellent. The size of that thing would be really annoying to have to keep with you in your sleeping bag to avoid freezing, lol! You can blow test the Sawyer if you suspect it has been compromised, but yeah there’s frequently no outward sign (occasionally the case may crack).
Isn’t crypto contagious from a single organism?
Difference in “nominal” and “absolute” pore size. “Nominal” means it will catch “most” (the 20-30% pass through you quoted) things that size, and “absolute” means it will catch (basically) all things that size.
idk, i'm sure it can happen, but i don't think ingesting a single Cryptosporidium oocyst will reliably produce infection.
If we’re still talking about UV-C…
There are a few portable, exposed, “wand” style devices. If all you want is short-range sterilization. If you want throw, I’m looking for one too.
Note: a lot of wands have a safety feature that turn it off when not pointing downwards!
Xiaomi has a few - this waterproof model, like the Steripen, called the paini or petoneer. There’s another one that looks like a microphone. Both use UV tubes. There are pros and cons between tubes and LEDs so you should check.
59S is another brand. They only use LEDs.
There are some products for milk bottle sterilizing at home, usually as a small cabinet. If you want more powerful sterilization, get one that produces ozone too.