Dont forget about the 6 or 10 gallons in the water heater. You have to sanitize it too. You'll actually need 66 to 70 gallons plus what the water lines hold plus what goes down the drain each time you open a spigot to fill the risers.
It's not going to hurt anything except biologicals by putting most of the bleach in the first bucket and a small amount in the last bucket.
I have a 2 gallon Reliance water jug with a 2 foot piece of tubing on it. I fill it half way then add all the bleach, then I top it off. I pour it into the tank, then top off the tank. I run it through the lines, fill the 6 gallon water heater. Then I add another 2 gallons with 2 ounces of bleach with the Reliance container then top off the water tank.
