Do/will plants and cyanobacteria produce Oxygen for use, and act as a CO2 scrubber? So the more plants and cyanobacteria growth you have, the more O2 you'll have and less CO2 inside the habitat module.
What all would the medicines be for? Besides generic healing of health if someone was out in the cold for too long or lack of O2?
What would be the purpose of fish? Scientific research, expansion of colonists diets? What is a way that the water in the algae and fish tank(s) could be used to maximum potential? Water is known to be a good insulator against radiation, so I think it could be used to somewhat shield the colonists and should be positioned to do that in the best, but practical manner. Of course, if you're wanting things to live in the water, positioning the fish/algae tanks on the very outsides of a habitat module may not be the best option. As they'd need a certain level of protection from radiation, and extreme cold. Maybe have the fish/algae tanks on the second level, that way the ground floor, and perhaps below-ground floor would receive extra protection from radiation, due to the water, but the water would also be fairly protected from the cold and radiation? This would mean the second floor would either have to have a lot of windows to allow sunlight in for the algae, and/or use UV lights perhaps only during sandstorms when sunlight is reduced even further, and/or another option that I just thought of; use only a few windows, but use an array of sun-tracking electric powered mirrors to direct sunlight into those few windows. I think the final 2 options are the best.
