steri pen by hydro-photon

http://www.uvaquastar.com

cheaper, lighter and easier to use (built in 1l bottle cap)

2 type 123 photo batteries supposed to be good for 70 liters (or 70 treatments – depending on water temp/quality you may need to double dose)

Yes, I have a Steripen, the newest. If you use 4 AA Lithium batteries it will purify up to 140 treatments each in 45 seconds. Mine weighs 5.75 oz with the batteries. Theoretically it would be enough for 4 people for 4 days. The other option is Aquamira, which would weigh about 4 oz. and you would have to wait for it’s chemical reaction to purify the water. The great thing about the pen is that it now fits the platypus bottles, so you can scoop up water and purify on the spot. Note: Use a coffee filter to filter debre.

My question is does it really work? I have been looking for actual users of this on a number of forums. Everybody knows about them but few have used them for any length of time. I undestand how a filter works but shinning a light in water to purify it sounds to good to be true. I would hate to find out it doesn’t work on the trail.

many yrs ago i worked as a clinical microbiologist in a hospital lab.

based upon my educational background at the time & my work/laboratory experience, i can unequivocably state that UV light can kill microorgansisms of many different types, including viruses, bacteria, and protozoans.

also, while employed as a graduate lab assistant, i have, more than once, witnessed undergrad students accidentally leave a glass petri dish near a window in a college lab. the result was that even though two layers of glass (i.e., the window & the glass petri dish cover) were filtering the UV light in the sun’s rays, the carefully innoculated media in the petri dish would always fail to produce any bacterial growth.

in a laboratory, UV sterilization (and also gas sterilization) is commonly employed when the items to be sterilized are not tolerant of super-heated steam sterilization techniques.

as with any means of water purification, the manufacturer’s instructions should be strictly adhered to in order to acheive the desired results. keep in mind, as the manufacturer’s instructions states, you many still need to filter the water until clear, prior to using the steripen.

i live & hike in the more heavily populated (relatively speaking) northeast. a fair number of farms & basically low lands & hills.

i also own a steripen & have used it. it appears to work, since i have not become ill drinking the water sterilized with the steripen. however, this is basically an argument from lack of evidence as 1) who’s to say the water was contaminated in the first place?, and 2) the number of times i’ve used it thus far is not sufficient from which to draw any statistical conclusions having a high degree of confidence.

i should also state that, at this point in time, my main means of water purification is still aqua mira. why? it weighs less.

hope this info sets your mind at ease.

I’ve used them on a 5-day hike to the Wind Rivers.

As an end user, I can’t tell you with any precision the percentage of “germs” killed. However, I can tell you that I felt completely fine drinking the treated water for those five days (not even the slightest hint of discomfort).

Maybe combining my unscientific experience plus the more technical post above will give you the user feedback you are looking for.

I bought the Steri Pen last year prior to a hunting trip in the Gore Range of Colorado. I used it for 3 days with no adverse effects. I felt very smug in my intellectual superiority and general all around cutting edge-ness (?) until I finally perused the literature enclosed and read that the pen doesn’t work in ice cold water, which is all I had access to up there in the mountains. That being said I think it makes perfect sense and I will continue to use it except in freezing conditions.

I’m fairly confident in the steri-pen’s ability to kill bacteria. It seems to work well in controlled lab experiments we’ve done with planktonic suspensions.

We are seeing some data where it loses some efficacy when the bacteria are attached to particles (biofilm) rather than just free floating in suspension, but this data is not conclusive and is early stage observation. Chemical methods such as chlorine dioxide still seem to work better when there is a significant amount of particulate matter in suspension.

UV seems to be reasonably effective against Giardia cysts, but I haven’t seen data on these two UV pen products specifically.

Is Aquamira really lighter if you calculate in the two part 1 oz bottles, the extra blatter needed so that you can still drink (unless you can wait), and the water to hold you over while you wait? And that is for just one person.

You can use tiny dropper bottles instead of the “full size” one-ounce bottles.

http://www.backpackinglight.com/cgi-bin/backpackinglight/microdrop_dropper_bottle.html

As for water, chances are that you would be looking for water well before you are down to your last drop. So, when you reach your water source, you can first mix the Aqua Mira, then drink up your remaining water, then fill up your bottle and drop in the purifying mixture.

I use two smaller dropper bottles for the aquamira to cut down on the weight and have gone 5 days purifying 4 to 6 liters per day. Concerning the extra baldder. I too faced the same issue, I used to use a 3 liter Bladder. Now I use 3 1 liter platypus bottles and work a rotation. I’d always be assured of some water being available and would refill and treat the other two as I move along. It is no problem for me to stop at any water source for 5 or 10 minutes to prepare the aquamira to treat 1 or two liters of water. I carry two caps to mix the Aquamira for two liters of H20. I use the wait time to pop off the boots and relax, snack or other pleasantries.

I just bought Aqua Mira, so no field experience yet. Since I carry two water bottles, I’m wondering if I can just mix the solution in the caps of these bottles — and leave the Aqua Mira mixing cap at home?

Whats funny for me is the last few trips I have gone on I have not needed to purify any water. I carried the UV and my buddy carried the Aqua Mira, but the water was from springs. It is just that the UV is soooo simple. Less to mess up and fumble with.

Who knows maybe the Steripen will find itself with the numberous stoves, pots, tents, pads, sleeping bags, backpacks, etc….. that I no longer use.

Does anyone know if the number of drops per liter is different from the AquaMira instructions when using the BMW MicroDrop Dropper Bottle? I noticed that the 0.35 oz dropper bottles require a change in the recommended number of drops.

A drop is a drop!

a drop is NOT always a drop.

this is a common misconception.

drop sizes vary depending upon various factors. on the most fundamental level (for our purposes), the “battle” b/t cohesion of the fluid molecules to each other vs. adhesion of the fluid to the dropper tip can affect drop size. the cohesion/adhesion issue is affected by the mat’l the dropper tip is made out of, the diameter & shape of the tip opening and the pressure at which the fluid is forced through the opening. temp of the fluid also plays a role. these issues are NOT unique to dropper bottles. tip opening/’jet’ size & pressure are factors in fuel atomization, i.e., in part – drop size, in both carburetors and fuel injection systems, as is temp.

the webpage for the 0.35 oz bottles indicate the proper # of drops of both AqM A & B (still in equal proportions) that should be used. it recommends an increase to 11 drops of each (despite my failing memory, i am sure of this b/c this is what i use).

the webpage for the micro dropper does NOT state the # of drops to use with AqM. it does however state, if memory serves, that it holds somewhere around 40 drops. ok. just checked. it is 40 drops. however, w/o more info, i do question one thing in the product description. the write-up also says treats up to 5L of water when used w/AqM. that would be true if only 7 or 8 drops (or less – an unlikely scenario) were req’d instead of 11 or more drops. We need a “judges” ruling on this point – Dr. J or anyone else at BPL/BMW – care to help us out here? How many drops fr/your micro bottle to treat 1L of water with AqM?

We haven’t done drop size measurements on the MicroDrop bottles yet.

But here’s a tip to decrease the number of drops you need AND extend that tiny little bottle that much more: use less Aqua Mira.

Halve the dose, double the treatment time. Read the article in the current issue (print) of Backpacking Light to at least prove to yourself that this works on bacteria.

I’m out of town now, but will put the drop size measurement on my todo list when I get home.

To be honest, I’ve been using 7 drops in our 0.35 oz dropper bottles for Aqua Mira dosing, in spite of the dropper size. However, I’m almost always letting the treatment period exceed 30 minutes.

Dr. J,

many thanks for the swift reply.

>>”double the treatment time” ==> good suggestion. i should have thought of that myself.

enjoy your trip.