Yes, but wasn't it Tommykib that said there was zero vis? And apparently, as Cave Diver observed, he wasn't in a hat, he was on SCUBA.
However, there is no reason to believe he did not go through the wash-down as would a hard-hat diver.
If he did mention zero vis, I can't find it now. Superlyte mentioned working in 0 viz himself but I took that to mean no viz because of all the silt being stirred up on his jobs.
Viz in the tank was mentioned to be crystal clear.