Yes, it will technically work. However you need to address two key concerns before attempting this:
1. You need to provide a way to keep critters such as fish and snails out of the standpipe to prevent it from getting clogged. If you use a strainer you need to be careful of algae, food, even nori sheets from clogging the strainer. We offer a large strainer if needed.
2. In the even of a power outage the water level in the aquarium will drop to the opening of the standpipe (overflow chambers help limit the amount of water that drains). This water level drop can be several inches. You need to consider if corals or heaters may become exposed to the air and the sump needs to be sized correctly to handle this volume of water draining.