DrCase said:
One of my filters is full of the small scrap PVC that comes off my truck daily
Looking at the gunk that comes out the drain ,it works fine
Actually, that doesnt prove a whole lot. It proves that the vortex manages to let solids settle at the bottom, perhaps also that the PVC tubes capture solids, but in so far they do, they would make the filter less efficient as biofilter. Not saying it aint working, and Im sure you have sufficient biofiltration for your pond, and I know how nice it looks, but gunk coming out of the very barrel that is (also) your biofilter, is not proof of it working well. Biofiltration works best in clean water, with no solids.
FWIW, I am using three barrels, 2 mechanical (first vortex + brushes, second vortex + large pieces of PVC) and one biological (plastic biomedia). The bottom drain of the first flushes to thick brown gunk. The second one is generally a lot more clear, the third one is pristine. After months of running, flushing the bottomdrain of the third still produces hardly anything but clear water. That doesnt mean the third doesnt do anything, on the contrary, its where the bulk of the biofiltering happens. The handful of originally white K1 I have in there as "control group" is nicely brown from bacteria. Just not dirty that flushing would clean it.
