IPW Industries Inc - Bulk Water Filter-Air Filter Refill Coconut Shell Granular Activated Carbon Charcoal 12x40 Mesh Choose: 5 Pound Bag

it's a great size. about a teaspoon full into a paper coffee filter that is held by a stainless steel funnel works really well for filtering tap water. it's a little bit slow so you could scale it up with bigger funnel and I guess use multiple coffee filters spread out. anyway it works really well to make the water taste better and filter chlorine and other things that activate a charcoal wheel filter. this 5 lb will probably last me years. You only need about a spoonful to filter gallons of water slowly through the powdered charcoal. there is some dust. so you might find some blackness In the bottom of your drinking container. it's not harmful but if you don't like it you can just pour the water through again and that adds more bits of charcoal dust to the filter. a side note. if someone were to drink accidentally poison a spoonful of activated carbon taken orally might be helpful. check the web for this use