As an aside about pure water being corrosive, ultrapure water is something else, as seen in the Super-Kamiokande neutrino detector
https://www.sciencenewslab.com/this-beautiful-golden-chamber...
>In order for the light from these shockwaves to reach the sensors, the water has to be cleaner than you can possibly imagine. Super-K is constantly filtering and re-purifying it, and even blasts it with UV light to kill off any bacteria.
>Which actually makes it pretty creepy.
>“Water that’s ultra-pure is waiting to dissolve stuff into it,” said Uchida. “Pure water is very, very nasty stuff. It has the features of an acid and an alkaline.”
>“If you went for a soak in this ultra-pure Super-K water you would get quite a bit of exfoliation,” said Wascko. “Whether you want it or not.”
>When Super-K needs maintenance, researchers need to go out on rubber dinghies (see above) to fix and replace the sensors.
>Matthew Malek, of the University of Sheffield, and two others were doing maintenance from a dinghy back when he was a PhD student.
>At the end of the day’s work, the gondola that normally takes the physicists in and out of the tank was broken, so he and two others had to sit tight for a while. They kicked back in their boats, shooting the breeze.
>“What I didn’t realise, as we were laying back in these boats and talking is that a little bit of my hair, probably no more than three centimeters, was dipped in the water,” Malek told Business Insider.
>As they were draining the water out of Super-K at the time, Malek didn’t worry about contaminating it. But when he awoke at 3 am the next morning, he had an awful realisation.
>“I got up at 3 o’clock in the morning with the itchiest scalp I have ever had in my entire life,” he said. “Itchier than having chickenpox as a child. It was so itchy I just couldn’t sleep.”
>He realised that the water had leeched his hair’s nutrients out through the tips, and that this nutrient deficiency had worked its way up to his scalp. He quickly jumped in the shower and spent half an hour vigorously conditioning his hair.
>Another tale comes from Wascko, who heard that in 2000 when the tank had been fully drained, researchers found the outline of a wrench at the bottom of it.
>“Apparently somebody had left a wrench there when they filled it in 1995,” he said. “When they drained it in 2000 the wrench had dissolved.”