I answered Possum up there before seeing your comment. I’ve had a Berkefeld for 11 years and wish I could buy a back up just in case. I do have a couple of spare filters. They make good tasting water.
I’ve read the Berkely filters don’t get the viruses but will otherwise turn swamp water into something drinkable. I’ve also considered suplementing it with a self made filter system using 3 stages. Cloth for the big stuff, sand, and then DE powder. DE Powder will get the bacteria and viruses.
I live in Florida and while theres plenty of water most of it on the surface isn’t very potable.