I see you both use the filter element in a gravity system, as do I.

Some friends of mine were using the blue bottle with the filter attached to filter water - if you do more than barely squeeze the blue bottle, you split the seam, as they found out - researched by them, the max pressure is something ridiculous like 4 p.s.i. !

I saw a couple of guys filtering water in the grand canyon using the sawyer filter atop a cheap plastic water bottle (not the blue envelope thing) - chatting with them, they had had the same poor performance/splitting blue bottle and switched to using a regular store bought disposable water bottle.

kind of a joke when they say that you can filter up to a million gallons of water with the sawyer filter, but I do like them over other systems, and yeah, I do need to backflush it frequently.