I’ve found some online sources as well. However I prefer to filter the water and not just treat it chemically. The Berky water filters work great and last a long time.
From Berkey’s web page:
Berkey Stainless Steel Water Filtration Systems
Compare the different size stainless Berkey water filter models to find the one that best meets your personal needs.
5 different size models to choose from. Ranging in size from the Big Berkey to the Crown Berkey.
High quality hand buffed 304 stainless steel offers the ultimate in sanitation, cleanability and quality.
All stainless purifiers come standard with 2 filters and can be upgraded with additional filters for increased water flow.
Depending on the model, the system can accommodate up to 8 replaceable Black Berkey filter cartridges.
Gravity flow design needs no water pressure or electricity
Each Berkey purifier element filters 3000 gallons of water.
A range of filter models filter from 3 to over 26 gallons of purified water per hour (depending on model).
Berkey FAQs
Lifetime replacement policy on all Berkey water filter systems for our registered customers.
Also from Berkey:
WHAT ABOUT VIRUSES?
The extremely small size of viruses make them difficult for any filter to contain.
Chlorine is the most convenient means of eliminating the water-borne threat of any virus.
Black Berkey water treatment method is an integral part of this method of treating virus-contaminated water supplies.
The accepted standard for the use of chlorine to kill water-borne viruses is 8 to 16 drops of chlorine (common bleach) per gallon of water. ( Better too much than too little)
Add the chlorine to the water in the upper chamber.
Note: Chlorine and its residuals are considered by leading authorities to be harmful to you health.
The Black Berkey Filter elements remove the chlorine and its harmful residuals from the chlorinated water, leaving you with ultra-pure, safe, fresh-tasting water.