I never was big on filtering/treating in the Quet. until 3 of my guide friends all got girardia at the same time.  Since we often go on trips lasting longer than a week, and then have a 2 day marathon drive home to get back to work, I really don't want to have the symptoms. 

We filter when we are too lazy to go offshore for water, or when our Polar Pure is recharging.  Now that I've heard Uncle Sam has practically snuffed out Polar Pure, I'll have to figure something else out.