I've been overthinking again. I have been toying with adding a splash pond to the chickens' enclosure to keep a couple ducks for eggs and special occasions. However, I recently learned the hard way that ducks are filthy. I mean, FILTHY. Now, you can read those words and think "yes, yes, I've heard that they can be", but you have no idea. I have a 100-gal fish tank buried in the garden. Until this week, there were a dozen goldfish living placidly in that water. The tank is filtered by an aquaponic herb garden. Aquaponics are practically stupid-proof: the fish squirt into the water, the bacteria convert that to food for the plants, and the plants clean and oxygenate the water for the fish. This system has survived my toddler dumping entire large cans of fish flakes into the tank- multiple times (yes, I've tried to hide the flakes from her, but she's a good climber). It's so efficient, my toddler can turn the water opaque with fish food and the system will be clear again within 24 hours. When I water the plants, I dunk the watering can in this little tank to fill it quickly with nitrogen-rich water. There's a float in the tank to automagically refill the tank with fresh (well) water, and in this way several gallons are changed out on a regular basis. This little system has been running just fine for over a year. Last week, I let three adorable little ducklings play in that garden while I cleaned out their enclosure. In just one day, they fouled the water badly enough to kill my fish. The whole balance went haywire- the water clouded and started to stink within hours, The next day, the fish were gasping at the surface. I tried to bail out a portion with a 5-gallon bucket and refill with fresher water, but I couldn't save it. :/ Okay. No ducks in the fish ponds. BUT... I live in the desert. I can't have ducks just splashing all that precious water all over the place, and I definitely can't dump several gallons a day to clean it out. SO... I want this duck pool to be part of an enclosed system that filters and recycles the water. I don't know how "hot" duck poop is, i.e., how many square feet of growbed are required per duck to keep up. Anyone out there have something like this? How much growbed per gallon do you have? How many ducks per gallon?