Make sure you watch what your fish are doing to your heaters. My oscar knocked my heater around so that the bottom of the heater was sticking out of the water by an inch. I was sitting at my desk when I heard a huge POP
and looked over at the tank and the heater was in flames "under water". I quickly unplug the heater and fished it out and the glass particles. No fish were hurt during this. So I replaced the heater with a better one that will not break with fish attacking it and made sure it was well below the water level. Those who have other means of having the heater in their sumps or else where are lucky.
And a word to the wise. Get the toughest heater that you can get if you are going to have big and aggresive fish. They have some now that are not made of glass.
And a word to the wise. Get the toughest heater that you can get if you are going to have big and aggresive fish. They have some now that are not made of glass.