I put in a pond in our basement. The basement is dry walled, heated and a/c. What would be the best thing to use to heat it. Its going to have 4 motoro rays and an alligator gar. What is the least water temp you could go with for these guys? Its made up of just a pond liner and timbers. It wont have a sump to put one in either. Would i even have to use a heater? Just looking for some ideas. Thanks for any info. Just looking to see what you guys use. Thanks again.