Fun fact: because of the height, to mitigate how hard the water feels when you hit it, the pool is filled with air bubbles that break surface tension.,(reply>), @Émile Jetzer By visibility in this case, they mean from the diver’s perspective. So they know when to come out of flips and twists and set up for their landing,(reply>), @Georgie F When you hit the water, surface tensions <b>is</b> important.<br><br>As for visibility, speaking as a lifeguard, the bubbles make it way worse.,(reply>), Bubbles are not to 'break' surface tension, which doesn't matter for humans. They're to reduce the density of the water under the surface, and/or to increase visibility.