Hi. What heater would I use for an IBC water storage container. 250 gallon, plastic. It can't touch the sides. What temp would work best so nothing would grow on the inside. I'd be using this to prevent the water from freezing. The tank would be outside. I'll use solar to run the heater, but maybe that doesn't matter. Thank you for any help anybody offers. I apologize for this not being related to the purpose of Reed2reef. But I thought people here would know best. I appreciate your help and time.