Hi - I use the Platypus Gravityworks.
I see on the specs that the filter is good for 1500L but what if I'm not really sure how much I've used it or whether it's still good? Sure, I can just buy a new filter cartridge to be safe but at $78 a pop I'm not excited to just get one if I don't need it.

Is there any kind of test or indicator as to whether it's still ok to use?

I always test it prior to a trip.

Know how to back flush, I think the worst that can happen is it will get really slow. There is a process to restore an older filter you can try as well.


Restore filter-

At the 1:10 mark in this video is the "how to" field test if your filter is still working properly:

Platypus Filter Test

timatkn: "I always test it prior to a trip.

Know how to back flush, I think the worst that can happen is it will get really slow. There is a process to restore an older filter you can try as well.

Restore filter- "

Thanks - yes for sure. My question is less about backflushing, though, and more about how do you know if the filter itself is no longer filtering properly? It's the microscopic germs I'm worried about.

Is it safe to assume that as long as clear water is flowing through at a reasonable rate, the filter is still doing its job? Or is it possible that something in the filter can break / wear out, and I wouldn't know it - and if so, how do people test for that?

portagerunner: "At the 1:10 mark in this video is the "how to" field test if your filter is still working properly:


Platypus Filter Test "

Perfect - exactly what I was looking for! Thank you

The air bubbles in the bladder has happened for me on a backflush when the filter is pretty new with only a few dozen gallons run through. We backflush when the filter starts to run slow to increase it's flow rate.

bottomtothetap: "The air bubbles in the bladder has happened for me on a backflush when the filter is pretty new with only a few dozen gallons run through. We backflush when the filter starts to run slow to increase it's flow rate. "

I had a brand new platypus quickdraw fail the test once as well. I bought two of them. One passed and one failed. Sent the failed one back. Apparently hollow fiber filters are relatively fragile and can be damaged in shipping from time to time so probably a good idea to test them when new as well as periodically during use (I plan to test mine every year now).

I also have an older gravityworks that I had accidentally had out in freezing temps that I thought for sure was toast, but it passed the integrity test so I'm still using it.