How much bleach to gallon of water? And let it sit how long? I'm going to de-winterize and sanitize entire fresh water system. I think I ask this every year. Going to try to remember it this...
I used 1/4 cup for my 20 gallon tank, and can still smell it after flushing another 20 gallons through the system. I'll be going with less next time. I let mine sit at least 2 hours, it's contact time not the amount of bleach that actually does the sanitizing.
I think what I ran into is the only bleach available is "ultra" ... even the cheapest store brand is "ultra" now, so whats in the bottle is more concentrated.