http://www.youtube.com/watch?v=YaOOmaGzx0g
Here’s an explanation of how a biosand filter for those of us with short attention spans. Seriously though, these things took a lot of research by many dedic…
http://www.youtube.com/watch?v=YaOOmaGzx0g
Here’s an explanation of how a biosand filter for those of us with short attention spans. Seriously though, these things took a lot of research by many dedic…