Originally Posted By: thseng
Take a look at the cross-section image on this page:
http://en.wikipedia.org/wiki/BioSand_Filter

The outlet comes out the bottom and then up to a level that is above the sand. When water stops flowing in the top, the filter doesn't drain completely, only to the level of the outlet.

That being said, I understand that they like best to have a continuous flow. It also takes some period of time with water flowing through it for a brand new filter to develop the layer of bacteria.


Keep in mind though that the biosludge (bacteria) layer needs oxygen. It is best if the water continuously falls onto a splash plate above the bacteria layer. The picture in Wikipedia is the next-best thing but the water level can't be over 2 inches deep over the biosludge. It needs to be that shallow so that oxygen can diffuse through the water to the bacteria.

-Blast
_________________________
Foraging Texas
Medicine Man Plant Co.
DrMerriwether on YouTube
Radio Call Sign: KI5BOG
*As an Amazon Influencer, I may earn a sales commission on Amazon links in my posts.