I recently came across a few videos from a YouTube channel by the name of Tech Ingredients and there were three that caught my attention. The three were videos where about DIY fridges, freezers and aquarium lights. Though in all three videos one thing caught my attention, the use of liquid cooling to divert heat from the appliances to warm another location, and in the case of the aquarium light video, heating the aquarium itself. I was wondering if anyone had any experience with similar attempts at heating your aquariums to cut the costs of heaters and issues with heater failure, or even the possibility of using said liquid heaters to somewhat heat outdoor mini ponds.