Filters

[markw]

Hello all,

I've always tended to use millbank and boil or Puritabs for making water potable, however, I'm thinking of giving a Pre-Mac MWP Water Purifier a try.

Now this may sound like a bit of a dumb question but how do know when the filter cartridge is spent. is there an indicator or do you need to keep a manual`count of water passed through it?.

Regards

Mark

 

[Tiley]

With the Pre-Mac, the end of the filter's life is easily discovered: it simply stops working. When you can no longer pump, then you replace the filters.

Personally, I hate the iodine taste from the Pre-Mac filter. Boiling is, in my opinion, far simpler, tastes better and is one less bit of kit to carry around. The down side is that you have to think ahead if you want a drink of cold water.

 

[capacious]

This probably isn't the best thing to say on a thread about water purifiers, but have you ever considered not using one?

I always drink my water as it comes, and have never been ill after what must be literally thousands of gallons of untreated water. All you need to do is choose your sources intelligently, and you'll be fine.

 

[British Red]

I would say drinking untreated water is highly dangerous in some parts of the world and more safe in others. Giardia etc. are not to be taken lightly

Red

 

[EdS]

yes but the traditional dead sheep 100 yadrs up stream is untreated water that genuine upland flavour.


Got to admit on days out I never consider treating upland water. Although I do avoid anything that looks to be peats - saves having to dig lots of holes .

 

[leon-1]

Pre-Mac is a good filter, but my major gripe with them is they are not very cost effective. They filter a certain amount of water and it cost £60 odd quid for one. The Katadyn mini will filter somewhere in the region of 7,000 litres of water IIRC, if you then want to sterilise further you can boil or add some form of puritab / sterilising agent.


That brings me on to another thing, if you are using the filter for more than one person and they are intolerant to iodine you could have a major problem.

The cheapest option by far is a Millbank Bag, they are not overly fast, but there is virtually nothing to go wrong with them

 

[capacious]

Giardia is not any where near as dangerous as some people would let you believe - at worst you get an upset stomach and diarrhoea for a day or two. Then...you are immune! Once you've had it once, that's it. There are far worst things in water than giardia, such as agricultural run off and heavy metals. Hence the intelligent selection of water sources!

 

[PC2K]

will the pre-mac remove gairdia at all?

accoording to this site, not: http://usachppm.apgea.army.mil/WPD/CompareDevices.aspx (scroll down)

And i haven't seen any claims by pre-mac about killing/removing gairdia and such.

 

[leon-1]

There are many factors in water purification inlcuding things like turbidity and water temperature.

Pre-mac do claim that they clear water of cysts and giardia are a type of cyst. The thing to note is that as mentioned before there are many factors to take into account, clarity / turbity of water, water temperature and contact period of chemical agent.

There have been studies that state that chemical sterilisation of water can take anywhere from 30 minutes to even more than an hour (in cold conditions) when dealing with cysts like giardia, that is specifically with iodine and the chemical agent in a Pre-Mac filter is Iodine based.

Some say that a rolling boil for one minute will do it, that is not neccesarily true either as this is a time for sea level in more or less ideal conditions. At altitude 3 - 5 minutes is far more likely. Effectively boiling water is far more efficient in many ways than chemical sterilisation, just for the fact that in six minutes on a reasonable gas stove at sea level you can have potable / sterile water, whereas you could be waiting between 5 and ten times as long with something chemically treated.

 

[Porcupine]

personaly i prefer boiling to some techo gizmo doin its job.

no parts to break,go missing or just plain fail.

 

[markw]

Thanks for the input folks. I'll stick with bag 'n' boil.

M

 

[Spacemonkey]

I use a Premac pocket travel well as it is so compact. Works for me, but I do think about where the water is gathered to begin with. When I was a kid, I would drink water straight from the Hampshire River Avon on the Royalty Fisheries. I was never ill from it, and I'm still alive...

 

[Bozle]

Definitely agree with boiling as the number one mthod of killing nasties.

Cysts such as gardia can deform to get though mesh smaller than their size- the consensus on this is that a 2 micron filter is needed to do a decent job of removing them. The premac is about 15 microns (from memory) so won't remove all of these 5 micron cysts (an active treatement would- I don't remember if the premac has this).

I use this

http://www.bwtechnologies.com/technology.html

when I can't boil, as it also gets rid of a preportion of heavy metals and toxins.
I've heard good things about the MSR kit as well if you want to check them.

 

[Graham_S]

i like the MSR waterworks. it filters well, has a good flow and is user maintainable with readily available spares.
it also screws directly onto a nalgene bottle for convenience while filling.
it's not cheap (although you can save a fortune getting it on ebay from the usa) but it works out among the cheapest methods per litre.

 

[TheMagicalBadger]

Due to advice and comments found throughout this site, I got an MSR miniworks filter last year and took it for a 4 day camp up a welsh mountain with only a few friends, a big lake and some sheep for company. I also bought a nalgene bottle as this was always mentioned as being able to screw straight into the bottom of the filter - which it did, and I was very happy with the filter it was so quick and everone else did all the pumping for me as it was something shiny and exciting to play with...

The thing that I've not seen ever mentioned (and considering MSR and platypus are owned by the same company you'd think they would) is the fact that the bottom of the MSR filter has a small protrusion that a Platypus hose fits onto perfectly.

So if like me you have a platy hoser, you simply pull off the mouth piece, squish out any air from the bladder, then attach the hose to the filter and start filling your platypus directly with lovely clean water! I took this one step further, in fact, and also got one of the huge platypus 6L water tanks with zip top, and the hoser end can screw into that and be filled from the filter too. Yes, I drink an awful lot when I'm active

Although I trusted the lake water was virus-free - one of the natives that took us up there has been drinking it unboiled/treated all his life - after filtering, I also used some MSR Swee****er chlorine solution (as much to see how awful it made the water taste as anything). If you stick to the suggested dose then you can taste it's in there, but its certainly not 'bad'. One drop too many and its gruesome. I found the chlorine taste seems to fade if you leave your sterilised water in the sun for an hour or so (the same reason not to leave a bleach bottle in direct sun,I gues) I've got some neutralising tablets to try next time too.

The year before, when I had no filter, I was boiling all the drinking water for Mrs Badger and myself and it frankly ruined my trip. I was using a 2L steel kettle on a gas stove during the day, and the kettle directly on the fire at night but the pain was trying to cool the water down to drink it, I took a 1L sigg-type bottle as it was aluminium and thus highly thermaly conductive and light. I filled it with hot water, put the lid on loosely then balance it upright in the lake edge to cool, with stones to stop it falling over. then poured the rest of the kettle into various aluminium pans with lids that I left on the grass to cool, but by the time the 2nd 2L was boiled, none of the previous batch was cool enough to go into my platypus so I just sat around a lot being thirsty And then on the 2nd night it started raining and didnt stop until the morning of the last day

So... the filter rather improved things this year, and the welsh weather behaved itself a bit better

Sorry for going on and on about my boring life again, but the platy hose/msr filter thing just seemed too important not to be mentioned.

 

[pothunter]

The BWT system www.bwtechnologies.com appears to be very good, mesh size 2 micron but they never have any stock, BF appaer to be buying all thier production.

 

[Tiley]

Having filtered the muck out of the water with your Millbank, have you thought about zapping the invisible nasties with a SteriPen? It uses UV light to kill off everything, literally in a few seconds, enabling you to enjoy your water cool. All pumps have their drawbacks - they take time, don't actually sterilise the water, need replacement filters periodically - and I suppose the SteriPen is similarly afflicted by relying on batteries but it does seem to be a good idea.

I've not got one and have thought about buying one, principally because I really dislike the chlorine or iodine flavours that are currently favoured and also because the marketing and scientific blurb seems pretty persuasive. If anyone has got one, it would be interesting to hear their take on it.