Why do you think the filter has to be replaced at about 200 gallons, because it gets too plugged up to function anymore.
Hmmmmmmm ................ back flush for free or spend $50.00 on a new filter.
P.S. Sawyer provides instructions for sanitizing their filters.
Sawyer's customer service is top-notch.
I had a questions about the proper way to backflush and clean the filter for storage since it wouldn't be used again for almost 6 months.
The cust svc rep spent a good ten minutes on the phone with me and said if I had any other issues to call back. He was very knowledgeable about the product and that means a lot to me.
As I said earlier we filtered water for 4 days for a group of 21 men who were going through 3-4 liters of water/day. I have no doubt we could have stayed out an other 4 days and been fine.
Gravity feed is the way to go!