Hi. This is our next video. In this video we upgrade the groundwater filtration system. We built 1 more tank on the top. We will have 2 times to clean water from the well. We create many layers of filters, originally layers of charcoal, gravel, sand and stone. charcoal is used to clean bacteria and heavy metals in water. Sand and stone are effective in water. We will continue to do new projects in the next video. Subscribe to our channel to watch the latest videos. thank you.