I have always been confused about when to shut off my filters. I have read that fish need a warmer area on the bottom of the pond in winter to survive. If I run my filter it will circulate the water and make the cold water at the top reach the bottom. Someone please tell me when to turn off my filters. I have a 4 foot deep pond that is 12 feet by 9 feet and live in New Jersey. It gets cold! Please explain what to do I have never found an answer. I have made it through two winters. But last winter it got warm and I had ammonia and lost a fish because I didn’t run the filters in winter. I’m confused and climate change does not help.