Each jar is 1500 ml with a plastic betta-safe plant or other decoration to hide behind. The bettas will all be in the dark where it is quiet to minimize stress. Each jar will have an aq salt to water ratio of 2.5:1500 to start with and if the betta does not get better or if illness needs more than that then i will change it, but that is the standard. Wondering if this is good? Also, I was wondering if bettas know like the smell of thier jar or what because I think that moving to an identical jar with identical plant is less stressful that waiting in a cup during 100% water changes, and then I can put the betta in a sterile jar every time. There will be four open jars for bettas plus more being washed. All jars are identical.