When performing the usual aquarium maintenance and equipment servicing, don’t forget one of the biggest workhorses of your tank, the return pump. Because these pumps are running constantly and rarely give us problems, we often overlook them when it comes time to doing preventative maintenance. If they are overlooked, normally not a whole lot happens. Unfortunately though, by ignoring them, you also run the risk of missing out on potential tell tale signs that let us know when problems are coming our way. With return pumps, both internal and external, the most vital part is the impeller. Over time, magnets can crack and impeller blades can become worn. Both of these can lead to a pump that doesn’t run very efficiently, and problems with the magnet can cause the pump to seize and burn up down the road. So, when doing that monthly, bi-monthly, or whatever interval maintenance, be sure to include the return pumps.