Backup filter for Isle Royale

Other than a filter removing them, only boiling will kill the eggs.

Take a backup dirty water bag and the backflush syringe. If you use a Platy or Evernew bag for clean water, that could be the backup dirty water bag. Check the fit first though, as many report issues fitting a Platy on the threads.

The only other way for the filter to fail is to crack due to being dropped or freezing. Shake it dry and keep it in a ziploc in your sleeping bag at night. If it does get dropped on rock, take the time to boil the water. If you can use a small fire, there's no need to carry extra fuel, but you'd probably want at least a 1 liter pot.

Why not take the syringe and a Sawyer mini as backup? The mini could work off of the bags you already have.

Thanks. Do you know what the difference is between the Squeeze and the Mini?

No matter what filter/ steripen I carry I always have a backup Life Systems filter straw filter in
my 1st Aid/repair kit (weighs about an ounce) I picked it up in a big box store for 10$ .

A friend who has no tolerance for clogged filters has used as a pre-filter:
http://www.dudadiesel.com/choose_item.php?id=PTFEP3S
for a few years.

Filtration is not a simple "catches all things larger than a certain size" thing so I would not trust that filter alone. But this filter media is designed to catch small solids and it does pretty much eliminate clogging of the primary filter.

It includes a stout steel ring at the top. That is easily removable using diagonal cutters.

"Do you know what the difference is between the Squeeze and the Mini?"

I believe that the Mini is just that, a smaller version of the regular Squeeze (fewer "tubes" in the filter). Less weight, but slower output. As a backup, no big deal.

The fittings are different as well. While the Mini still can use the Squeeze bags it also has inline hydration hose fittings.