Bleach is incredibly toxic to microbes. So toxic that there is really no need to do a 5-1 water/bleach solution....such a high concentration would necessitate a gas mask in your home for a week...lol
To sterilize 50 gallons of water only requires about 2 tablespoons of bleach...assuming the water is clear and the expected bacterial load is relatively small. I have drunk lake and river water for years by putting a single drop in a canteen full of river water and waiting 10-20 minutes to drink it.
I would say you should only need to use about 1T/10Gal to sterilize your tank. Remember that bleach does not contain stabilizer and so will evaporate and be used up very quickly...say 6 hours with the pump(s) running.
If I were you I would dose the tank once every 6 hours and run the pumps. That will be enough to serve cold soup out of the tank after about a day.
At that small of a concentration, you should hardly be able to smell it even with your nose down by the water...way less than a swimming pool.
A higher concentration would sterilize faster, but with the addition of time...a very small amount of bleach will sterilize anything.
Use plain bleach. Don't get the scented bleach or bleach with other additives. Also, it is getting hard to find regular bleach, so know than my recommendations will work fine for regular or the 33% more concentrated bleach sold at Wal-Mart.
Good Luck!