As some of you know, I teach STEM classes to middle school students. One of the our projects this year was to build an all in one using a 20 long. The kids were very proud to put this together. We kept a pistol shrimp and goby which led to many great learning opportunities. Recently inspired by a Pratt University project "Anemone in a Jar" I am planning a project that might encourage students to keep a little piece of the ocean at home. I have a couple of questions. Since it will be necessary to change water often, do you think using regular tap water instead of RO will be ok? Will it work without water circulation or a heater? What is the most inexpensive light option? What about a soft coral frag? Any advice would be greatly appreciated.