Saw that the 'best places to buy chlorine' thread was closed, wasn't sure why. I've typically just done the 2.5 gallon refill at Leslie's, or bought bleach at Walmart. However, recently I was at Home Depot and saw they do 6 packs of 5.25% generic bleach gallons for 7.99. Despite being less potent, this is still the best deal I can find. Seems to work like any other chlorine after weeks of use and testing (of course adjusting for the lower %). This has dropped my chlorine bill a good chunk so though I'd share! I'm in Tampa, FL.