Not long ago I found some neat aluminum/plexiglass sight glass inserts that screw tightly into the 38mm ID of the triclamp ports I use on our kettles. These are only temperature resistant to 80C but perfect for a small window into the mash tun. I wanted to view the action underneath the false bottom during mashing, so I put them to use with my false bottom setup on the tall false bottom stand.
I was hoping for a bit more, but the water quickly turned too cloudy to view much anything of interest. But it was still enlightening to see the moment of mash-in and witness the amount of particulate that passes through the false bottom before the grain bed filter is set. Just another reminder to clear the area around your kettle outlet of grain matter before lautering, if you want to keep this material out of the boil kettle!