clockman
New member
Tough question to answer as most of us have a tank full of live rock for the primary source of biological filtration. Do you have a tank full of live rock? If so, most of your biological filtration is taking place there and not in your sump. If you don't have live rock then you will have a build up of nitrogenous wastes that will harm the fish but they will die long before that if you don't aerate the water. Keeping your biological filter alive is important but I do believe it will recover quickly even without the addition of a power head to the sump. Dead fish in your main tank.......well, that's another story.