Ah.....I'll bet THAT's why it turned gray--all that cal-hypo at once...It CAN do that...So "sanitizer" is what? 12.5% Sodium Hypochlorite? One gallon then is about equal to 2 gallons of regular bleach (But that's on 5.25% you say and double is 10.5%...) Yup. Odds are the 12.5% has degraded--it does that a lightning speed at higher concentrations and if it costs more than 2 gallons of regular, don't waste your money. In my part of the country, reg. bleach is about $1.70-$1.80/gallon. But "Sanitizer" (they call it "Liquid Shock" here but it's the same stuff) is $3.99/gallon. So, unless you MUST have fewer jugs, it wll cost you between $.20 and $.30/gallon more to use the "sanitizer".

I don't see the point. Even 6% bleach is cheaper on an ounce by ounce basis.

Just use two gallons of bleach where you would have used one of the fancy stuff.