We buy barrells of chlorine every spring. It is not liquid, but powder, (or we can buy it in plastic wrapped tablets for the pool floaters inside a barrell). Our pool is 30,000 gallons, and the barrels last us all summer in extreme heat. We don't measure the barrells in gallons, but in dry weights/pounds. I went into the garage today and thought about what size body would fit in one of the barrells. It would be a squeeze, but possible. We also use other pool chemicals - like muriatic acid - which would do far more harm to any biology than chlorine would.