Two overhead wet/dry tubs loaded with bioballs and some lava rock. The are ran by a pr of dc pumps that drain the water into the drip plate/floss area then fall over the bio media and then cascading back into the tank. I wanted to create bio towers but since the tank is 4 ft tall i needed to biuld stands for the filters to sit upon and alow them to drain back by gravity. I change out the floss every 7 to 10 days on both filters. I run a uv as well but its purpose is for water clarity. I also have a drip system that adds 5 gals per hr 24/7. The overspill from the tank runs into the bushes. I also invert this drain when doing the occasional water change by adding on a 14" pvc pipe. Once it reaches the end of the pipe it cuts off and i use the drip system to refill the tank minus using the emitter to refill the tank quickly. Once its filled back up i attach the emitter again and leave it be.