I have the 3L Katadyn Bfree water filtration system (https://www.katadyn.com/us/us/37914-8019640-katadyn-befree-3.0L_usa) and have used it the past 2 years. We like this gravity filter setup but fill it often with 4-6 people in the group. I recently purchased the 4L Hydrapack Seeker (https://hydrapak.com/products/seeker-4-liter) and an additonal Katadyn filter so that we can have up to 7L of water between the two units in camp. Anyone have any experience with the Hydrapacks or this setup?

We used the Befree and Hydrapak on our most recent trip over Memorial day it and it works well. I was very impressed with my previous DIY sawyer mini gravity filter using a MSR dromlite bag but the Befree is even lighter and packs smaller.
As long as the filters hold up I think I've found my new water filter setup. :)

They work great. I originally bought the Befree with the 0.6L bag and use it during the day in the canoe and any time we are out hiking. Picked up a 2L hydrapack that i use with the Befree in camp as a gravity filter. At least on the 0.6L bag it actually says made by hydropack on the back of it.

If you are interested in the future on a sale this winter i picked up one of the 2L bags from CNOC with the 42mm threads to use with the BeFree filter. Link is below. I really like how the end opens up so that you can scoop the water right into the bladder. I have not tried it in the field yet but this company gets great reviews from through hikers using the version for the Sawyer filters.

CNOC 42mm

I'm looking forward to trying it. After reading some reviews I have gone about preparing the 4L seeker for use by filling it with hot water-baking soda-lemon juice-...freeze, thaw, repeat, etc.

I will have experience with it on the 15th of June. Just bought a Sawyer bladder (3.78 liter) last week for the same reason. Even with just the two of us, we filled it up almost constantly. Maybe we drink too much water. Probably should have bought 2. I plan on filtering through the Katadyn into the bladder, and then refilling the Katadyn.

I'm not sure if this unit had the rubber/chemical taste when delivered (didn't try it) but it doesn't seem to have it now. That baking soda-lemon juice - freeze-repeat treatment may be the ticket. I have put so paracord on the 4L seeker so that it can be handled/carried easier and also put some on so it can be hing like our 3L BeFree.

I emailed Hydrapack as I didn't get a small poly carry bag for mine when purchased. See what they say, but can always find a bag for it.

We have the platypus gravity filter.

Then I started hiking on the SHT (Superior Hiking Trail) and have tried the BeFree on recommendation from SHUG. Since then, I've also purchased the larger BeFree, and now operate with all three in the BWCA...

We have the Gravity Filter, the 3L BeFree for very quick water, and the 1L (Which I carry on hiking trips) for day tripping.

Love my BeFree water filters! They're AMAZING!