Started the trip filtering a litre in about ninety seconds, by day four it was taking five or six minutes and my hands were cramping. I backflushed with the syringe every evening with filtered water. The sources were mostly clear alpine creeks except one silty lake outflow on day two. It's got maybe 300 litres through it total. Do I bin it or is there something I'm doing wrong?
Did it freeze at any point? A single night below freezing with water inside will crack the fibres invisibly, and the symptom is usually the opposite — suspiciously fast flow — but a partial freeze can also present as reduced flow. If nights were near freezing, sleep with it in your quilt.
This is why I stop trusting a filter that suddenly flows better than new. Fast is bad news.
Lows were around 40F so probably not, but that's genuinely frightening as a failure mode because you'd never know.
300 litres is nothing, these are usually rated in the thousands under ideal conditions. "Ideal" is doing a lot of work in that sentence though. My real-world number before flow gets annoying is more like 400-600 litres on typical mixed sources.
Carry a backup on anything longer than three days regardless. Two chlorine dioxide tablets weigh nothing and mean a dead filter is an inconvenience rather than a trip-ender. I've used mine exactly once in six years and it was worth every gram.
@litercount_lou · 6mo ago · 3 replies
Not ruined, almost certainly the silty lake. Fine sediment packs into the hollow fibres and evening backflushing with a syringe barely touches it once it's set.
What actually restores flow at home:
Field prevention is the bigger lesson: for anything silty, let it settle in a dirty bag for twenty minutes and pour off the top, or prefilter through a bandana. Two minutes of patience saves the filter.
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@tomato_tobin · 6mo ago
Warm backflush plus a vinegar soak got it back to about two minutes a litre. Not new, but usable. Prefiltering from now on.
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@drainfield_dave · 6mo ago
The tap adapter is worth the few dollars. Household water pressure does more in thirty seconds than the syringe does in five minutes.
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