Is there an activated charcoal filter available to be used with an in-line filter (piggy-back style)?Somewhat along the lines of source (bladder, bottle, whatever) – hose – in-line filter (go-flow, Sawyer, whatever) – hose – charcoal filter(for taste, chemicals, etc.) – hose – mouthpiece. (Order not significant)Basically I’m looking for particle, biological, taste filtration that’s portable.