Now I need to put on my serious-science hat and do a test of multiple factors.
Plan: Prepare large volumes of two parallel mixtures of GFAJ-1 in AML60 medium, one with 40 mM arsenate and one without. Then place replicates in many different culture conditions. Plastic screw-cap tubes. Glass screw-cap tubes. Loosely capped glass tubes. Loosely capped plastic tubes. Tiny tubes. Big tubes. Foil-covered plastic flasks. Foil-covered glass flasks. Screw-capped glass bottles. Screw-capped plastic bottles. Large volumes of liquid with little air space. Small volumes of liquid with lots of air space. Stationary. Gently rocking. Shaken, not stirred. Vigorously agitated.