| Here is a drawing based on Garrett's design. Pretty simple to make with a 55 gal poly barrel, bulkhead fittings, and uniseals. Standard stuff for DIYers.
This filter is not actually "Back Flushed" per say, the flow is not reversed. When flushing you don't stop the flow, you just open the valve to waste, close the valve to the pond, open the vent valve, and turn on the blower. On mine I am using a short length of clear PVC so I can see when I am getting clear water out. The air from the blower will stir up the beads, dislodge all the dirt, and flow it to waste. Pretty nasty stuff comes out. |