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Backflushing MSR Gravity Filter

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Backflushing MSR Gravity Filter

Postby js_radford on Wed Feb 18, 2015 9:41 pm

I found directions on back-flushing lousy. To do properly, I seemed to need yet MORE equipment, namely a special extra bag (NOT included) just for the clean backflush water - open to air. Annoying! So I modified the included backflushing cap for my wide mouth water bottle as in photos, showing my add-on vent tube, allowing air to enter the capped water bottle and so not impair the backflushing process.

Also, I found directions for the filter generally unhelpful. To wit, they should say very clearly to "let water fill input tube BEFORE attaching to filter unit". This prevents air bubble blockages. Once I started doing this, output flow is much, much better both for normal filtering and for backflushing.

Today, while backflushing, I was careful to fill the input tube to backflush BEFORE attaching it to the filter unit and I backflushed a full quart in less than a minute! That was a vast improvement. Vast.

So ... no need for the silly extra weight/bulk of the backflush bag. Hopefully the backflush cap fits your water bottle. If so, that with the vent tube add-on, you are set for VERY fast backflushing.
MSR backflush cap with vent tube.jpg
Drill hole so doesn't damage cap and doesn't leak.
MSR backflush cap - drilled hole and vent tube.jpg
Tip vent tube up just above horizontal.
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