The next step in getting our system up and running was to finish the bell siphon and box system which will become our grow tray. We decided to use a homemade bell siphon to drain our ebb and flow system because it is cheap, easy, and reliable; it relies on gravity and has no moving parts so there is very little chance for mechanical breakdown. The picture shown below is our bell siphon. The valve itself is a system of two pipes that work together to siphon the water out of the tank at a predetermined level and stop the siphoning at another predetermined level. After the group installed the valve, we filled the box with clay spheres (Hydroton) which we will use for our growing medium.
In order to germinate seeds soon, we need to be sure that we have a healthy growing environment for both our fish and plants. To do this, we needed to decide what plants to grow based on the knowledge that our fish tank should be between 60ºF and 70ºF and have a pH between 6.5 and 7.5. Also included in our research was what plants grow well together; in other words what plants are companion plants. Companion plants are different species of plants that produce a chemical or nutrient byproduct that is advantageous to other plants. Finally we had to consider what plants can reasonably grow to harvest by the end of the semester (this criterion made us hesitant about fruiting plants). With all of these factors taken into account, we decided to grow Lettuce and Radishes. These are fast growing, resilient, companion plants.
Finally, we ended the day by testing the chemistry of our fish tank. It turned out that the pH of our tank was a little high, around 8.5. I added about 10-12mL of pH down which rapidly dropped the pH to 6.5. Word of wisdom to anyone else that wants to use it: use it sparingly. A little goes a long way.