Just a fair warning I have owned a few Cobalt Neotherms and have had issues. I used them on an apex so would power on and off so not sure if that is why. Twice I woke up in the morning to a terrible smell. The first time I thought the house was on fire and I went running to see what it was. Found the root of the smell and figured maybe it was the heater. Put my hand in the water to check it and it lit me up. It melted and released a terrible toxin in my water. My skimmer went nuts and I lost some coral. It was never out of the water was always submerged and clearly failed in the on position. I got that one replaced (I was using 2) and a few weeks later (and some dead corals) I woke up to that same smell. It happened again.... I now use Ehiem Jäger and love them. Never had any issue.