@Sophistifunk I was thinking about that too, but then, if it's all closed system where I'm just pumping the air around, and I can insulate the tubing, the efficiency loss shouldn't be huge. I mean, if I'll have the freezer filled up with water, like, 80% up, the air that sits above the water shouldn't contribute much to heating, no? I'm kinda thinking it will be more efficient than having a regular UV "filter" thing because those things really warm water up