A question has been raised about the quantity of Concentrated Bleach to put into water drums. Regular bleach is 5.25% Sodium Hypochlorite and the new Concentrated bleach is 8.25%. The manufacturer just reduced the water volume by 1/3. For drinking water, the drum label quantities of 2 tsp for 15 gallons and 7 teaspoons for 55 gallon drums is a minimum to keep the water safe. The minimum quantities for Concentrated bleach are 1-1/3 tsp for 15 gallons and 4-1/2 for a 55 gallon drum.  If you use the original listed amounts, 2 and 7 tsp, there will be no harm as these were listed as minimum quantities.