Isle Royale Forums

Just checking things off (and double/triple checking) my list as my trip to Isle Royale gets closer (Mid-July).

Does anyone have a water filter protocol they've used and trusted while on the island? I'm thinking about filtering water multiple times through different filters before I use it in my bottles or reservoir. Is that necessary or would one filter be enough?

Right now I have a Katadyn BeFree Filter on my bottle and a MSR thru-line filter on my reservoir. Is there any need to add another filter system/protocol before that?

On Isle Royale, it is recommended to use a 0.4 micron or finer water filter. The BeFree and MSR in-line filters are 0.1 and 0.2 microns, respectively. You should be fine with that setup.

Thanks IncaRoads, that's what I was thinking, just wanted a little confirmation!

I use a Sawyer and if I am in dirty water (edge of inland lake) pre-filter through a T shirt just to keep the solids out of the filter

Based on a suggestion here many years ago I use a coffee filter over the inlet.

+1 on the pre-filter. IR sources can be mucky/gritty, which can clog a BeFree in a hurry. While I admire the multiple use aspect of the t-shirt method, I use a coffee filter: I keep my cookpot handy, and use it to scoop from the water source, then pour the water through the coffee filter into the squeeze bag.

Trying to wrap my head around the T-shirt method. Is this a clean T-shirt (now soiled and wet)? A dirty T-shirt (now more soiled and wet and less available as an emergency back-up)? A T-shirt that is currently being worn (some acrobatics involved)? A T-shirt currently being worn by an unsuspecting companion (the companion now lying in the drink and feeling betrayed)?

An Alaskan bud told me he uses coffee filters as a water pre-filter. Quite light for sure.

backwoods doc wrote: Sun Jun 12, 2022 3:15 pm Trying to wrap my head around the T-shirt method. Is this a clean T-shirt (now soiled and wet)? A dirty T-shirt (now more soiled and wet and less available as an emergency back-up)? A T-shirt that is currently being worn (some acrobatics involved)? A T-shirt currently being worn by an unsuspecting companion (the companion now lying in the drink and feeling betrayed)?

It had been my t-shirt, but now it will always be the unsuspecting companion. much better.

Iconic wrote: Sun Jun 12, 2022 5:52 pm An Alaskan bud told me he uses coffee filters as a water pre-filter. Quite light for sure.

Back when I pumped, I would use a coffee filter for the inlet. Worked great. Now I use a Sawyer.

Using a gravity setup, I just let it sit a little longer in the dirty bag to settle out. If I'm not using a gravity set up, I just to keep the debris to a minimum by being careful about where and how I collect. I always have my syringe if I need to back flush my Sawyer.

Does anyone see the need to bring a purifier along or just throw some aquatabs in my bag just to be safe?

I don't use a water purifier or Aquatabs. My main concerns are Giardia and bacteria, and water filters take care of those just fine.

I've learned that there's a difference between a water purifier and a water filter. A purifier has much smaller pores that can remove viruses. Filters remove bacteria but generally not viruses.

The park's official recommendation is to EITHER use a purifier, or use both a filter and chemical treatment (like Aquatabs).

I've only ever used a filter and have been fine -- I agree that giardia especially is a major worry, and filters can manage it. But I would NOT use only chemical treatment.

This may deserve it's own thread but with the talk of pre-filtering, I'm interested to learn how all the various sub-micron filters handle the Tannins found in most inland waters. This report would include how well they remove it and how often they clog (assuming visible particles have been pre-filtered) thus requiring maintenance. Tannin is another name for Tannic Acid which is the main chemical that gives the water varying degrees of a brownish tint. Tannic acid is harmless but at strong enough levels can add a bad taste. It is the product of fermentation of the various organic material available and is actually based on a very complex sugar molecule. There are filtration systems that supposedly remove it (although I'm thinking not suitable for backpacking) based on ionic exchange systems, some using a 2 stage chemical treatment.

Tannic acid is soluble in water, so you get a 100-percent homogeneous solution(theoretically). A filter wouldn’t make much difference. Some chemical adsorption (activated charcoal, ion exchange media, etc) would be needed, which is how a home treatment system would typically work. I always like the way high-tannin water looks - picturing Taquemenon Falls in my mind. Like Iced tea. All the fluffy wind-borne stuff floating on the surface that you cannot see on less-brown water. The foam that naturally occurs as a result of natural saponins, I think they’re called.