http://www.walmart.com/ip/Clearon-Bleach-Tablets-32-count-5.64-oz/27457178
I buy a bottle or two every time I go to Walmart. They are in the cleaning products aisle by the liquid bleach.
StefanieQ
Hydrogen peroxide may also be a suitable alternative .... https://www.google.com/search?q=Pur...s=org.mozilla:en-US:official&client=firefox-a
hydrogen peroxide has a short storage longevity like bleach .... make sure it hasn't turned to water