I’m setting up my first salt water / reef aquarium. I have about a 45 gallon tank lagoon style, with about 20ish gallon sump. I was given some working eheim heaters. How do I go about setting them up? Do I use just one? Does it go in the sump by the protein skimmer? Or should it go in the tank. It’s a glass heater and I don’t have the suction cups so it would just have to lay down. Does it need to be turned off every water change? Thanks