Setting up your aquarium
Decide with the class the type of aquarium that you are testing (e.g., water only, water and Elodea, water and fish, and water, Elodea, and fish).
Place a light probe near your aquarium and close enough that it can be connected to one of the computers used by your group. The light probe needs to be mounted in a plastic cup (outside of the aquarium) to provide a stable support for the probe. Inverting (turning upside down) a plastic cup and punching a hole through the bottom to extend the light probe upwards works well.
Obtain a clean and dry aquarium. Fill it with the exact amount of "aged" water that your class has agreed on. Tap water often contains chlorine that is harmful to fish. When water is exposed (or aged) for one day to the air, chlorine evaporates into the air. If your group has decided to test their aquarium with additonal items (Elodea or fish), place them into your aquarium.