Here are some close ups of the Flowranger FR3500 back flushable waterfall filter. The water will come into the filter at a tangent. The drain out of the filter come out the side but as you can see from one of the photos we have modified the drain to draw from the bottom center of the filter. I have the drain plumbed into the blue 55 gallon drum (notice photo in water change thread) that is pumped to the orchard for cleaning the filter.
The large manifold assembly is the airboil system. In most applications the FR3500 is used as both a mechanical and biological filter so typically, this airboil feature is for back flush assistance but in this application since I am using a SIEVE and a W. Lim's Wave 24 with Kent Wallace's Static Pre-Filter assembly the filter will be primarily serve as a biological filter. I will keep the filter aerated at all times for maximum beneficial bacteria growth. The airboil manifold also serves as a rack to hold 36" Matala Rounds. The FR3500 comes with two 36" Matala Rounds but I think if I modify the airboil manifold I can squeeze in a third Matala Round.
The Pond Digger