Bottle Biology

 Save your bottles for Bottle Biology: TerrAqua Column, Compost Column, and an EcoColumn.  EcoColumns are stacks of 2-L bottles, usually one layer is a terrarium and another an aquarium.  (Here are excellent instructions.)  Start with an easy 2-L Bottle Ecosystem, an example of an open ecosystem.  Have a plan for the fish after the project—such as a friend with an aquarium, not a flush down the toilet.  There are commercial kits, such as Aqua Farm.  The 2-L bottle systems can work well.  Aquarium test strips are fine for testing the water in the bottle aquarium.  Here is a basic guide to using test strips in any aquarium. When my class built EcoColumn, they had one goal: keep the fish alive.  But, hey!  You do you!