Well the filters must have caught up today... I no longer have muddy foam on the surface, and the water finally looks clear again. Must be time to throw in some more gravel!!!
I'm kinda stuck right now. On each of my barrels, I have two holes for threaded 3" pipe fittings as the outlet spouts. I cannot seem to get these to stop leaking, and I think it's mostly because of the curve of the barrel. Currently I sanded a concave surface into the outer fitting so it sits flush to the barrel, then I screw the inner fitting into place. I made gaskets out of extra liner material, and put one inside and one outside the barrel, but it still leaks. All I can think of is I need to make a piece to go on the inside of the barrel that fits to the inner curve, but has a flat side so the fittings are all laid flat against their respective surfaces.
This picture shows the threaded couplings I am using. The threaded piece goes through the barrel from the inside, and the other piece has the concave surface to match the curve of the barrel. If I can't figure out something to seal these up using the rubber gaskets, I may have to simply silicon one part in place in the barrel.