Over the last few days I've been getting into big reactors. I've been messing around with them in my test world and I seem to have found a design that I like 7x7x5 with 5 fuel rods in an X shape in the middle. Now, I have a couple of questions. Firstly, what is the most efficient cooling liquid that is not gellid cryothem or whatever its called. I don't have access to that. Also, when my energy cells are full, should I shut it off and what would be the best way for me to do that or should I leave it running?