UPDATE! I started cycling my system a couple of weeks ago and things are looking pretty good. The down side is that the temperature keeps dropping to low during the night to allow me to add fish and plants. Hopefully in a week or so that will change. Meanwhile, I got bored today so I built a swirl bio-filter and added to my little two barrel system. It is a 35 gallon blue barrel with the top cut out. The water enters through the side of the barrel about 3 inches from the bottom and is designed so that the flow creates the swirl. The water exits at the top through a standpipe arrangement in the center of the barrel. The top of the barrel that I cut out was used as a baffle. I drilled a hole in the center of the top and threaded a female pvc coupling through the hole. The baffle sits on the standpite about 10 inches from the bottom. Sitting on top of the baffle is all the polyester quilt batting scraps from my wife's quilting projects. Lots of surface area for bacteria to grow. I may add some air stones to the bottom of the swirl filter to increase the DO. I don't have any way to check the DO right now so I guess best to err on the side of caution. We will see how this design works.