Hadn't seen this picture before so I looked into its validity (nothing personal, OP. Standard practice to check) and....yep, the text matches the image.
News cameras began rolling. Brock told the white swimmers "you're not putting these people in my pool", and—"with exaggerated gusto", suggests Warren —went to his office and brought out a 2 US gallons (7.6 L) drum of muriatic acid and poured it into the pool. This was a cleaning fluid, and Brock was "screaming that he would burn them out", comments Branch. Brock also yelled that he was "cleaning the pool", a presumed reference to it now being, in his eyes, racially contaminated.