I was referring to the treading, not the retrieval. I don't believe it requires the treading anymore. Probably too many people failing it.
Ah yeah, I did the brick treading when I initially certified. We were treading water for 3 hours one day. I passed the love onto students when I was teaching. LGI class had us 'saving' a 6'5" 'drowning' dude that outweighed me by a hundred pounds with no fat at all. Like swimming 250 pounds of bricks across a lake all at once. Bricks that were actively trying to fight you.
What is real funny is when the 6'5" guy blows his air out Dude would do that to the girls when testing to make them panic.