Intermarin Calcium reactor ?

Have a friend that is selling one of these but I cant find any info on it. If anyone knows anything about these please let me know.

Also, Can a CO2 tank and regulator be used on any calcium reactor or is there some kind of size matching that needs to be done?

Question 2. Any size co2 tank will work. I have a 10lb. My friend has a 5lb. Yet another friend has a 25lb or something huge like that. As far as regulators, they need to fit up to the co2 tank.