As Dan described in a previous post, the Productive Collective is continuing aquaponics research this winter through several versions of Window Aquaponics Units (or WApUs!) in Davis Sq., Inman Sq., and Back Bay at the Boston Architectural College. Here's the latest on our most developed system.
WApU Davis uses a 'solids only' filter (as opposed to a bio or carbon filter) so that we can cultivate the naturally occurring bacteria that break down ammonia (fish waste) into nitrate plant food (nitrate).We are using a pump on a timer (15 min. on/30 min. off, 24 hours a day!) to transport the water from our fish tank to a 'flood and drain' grow bed. The nutrient rich water feeds the plants and returns clean the water!
With the WApU Davis system, we're employing mature house plants. The plants live in baskets filled with an inert clay pebble growing media so that they can be easily rotated to receive maximum sunlight.
*In this photo you can see the intake and return lines as well as the silhouette of the water line and the baskets in the grow bed.
WApU Davis uses a 20 gallon heated tank and it is currently populated with 5 tropical 'community' fish of the Platy and Swordtail varieties. Cute little buggers indeed...
The PC collects temperature, pH, ammonia, nitrite, and nitrate data for each WApU daily. WApU Davis is currently experiencing an uptick in ammonia levels and are beginning to see nitrates form in the system after only 5 days!