Quote Originally Posted by RobertB View Post
They were shown putting some kind of sealant on. That said, it's only good when the sun is out, so rain darkening the horizon and nighttime are two obvious scenarios showing it's not in any way reliable.

?? I don't think that reliability is going to be an issue when the alternative is cave darkness. It's not like they are installing these in hospitals.


There is a cool Colorado company called IDE, out of Lakewood, that makes things like this for poor countries. Their most famous products are a bamboo treadle pump (pumping water down to 7 meters) and a ceramic water filter.