I have always had freshwater with my heaters in the tank. I will be converting to a saltwater tank with a sump filtration system. I have read where many people place their heaters right in the sump. Wouldn't this cause the heater to run almost constantly because of the constant flow and reintroduction of cooler tank water? I realize it is all the same water but isn't that why you buy a certain wattage of heater per gallon tank size for when the heater is in the tank, but my sump is significantly smaller capacity than my main tank.??? Wouldn't this mean you are using more electricity($) than necessary? Help me understand this!