Return Pumps Explained: What to Know and How to Choose

A return pump is the heart of any sump-based system circulating water from the sump back into your display tank. It drives filtration, maintains oxygenation, and keeps the entire system running smoothly. Choosing the right aquarium return pump is essential for long-term stability, especially in reef tanks where consistency is everything.

At Top Shelf Aquatics, we carry a curated selection of return pumps from brands known for performance and reliability like Sicce, Reef Octopus, Ecotech Marine, and Neptune Systems. Whether you're upgrading your system or building out a new tank, you'll find reef tank return pumps that deliver quiet, efficient, and dependable flow.

What Does a Return Pump Do?

In a sump-based system, the return pump is responsible for sending water from the sump back up to the display tank. As water overflows from the display into the sump via gravity, the return pump completes the loop powering circulation and ensuring that filtration, heating, and other equipment in the sump stay active.

If the return pump fails, water movement stops between the sump and display. That can reduce oxygenation, impact temperature stability, and disrupt biological filtration especially in reef tanks where consistency is key.

Choosing the Right Return Pump for Your Aquarium

The right return pump ensures stable flow and long-term reliability—but not every tank has the same needs. Here are a few key factors to keep in mind when selecting yours:

• Tank size and head height: Your pump needs to push water vertically from the sump to the display. The higher the distance (or the more complex the plumbing), the more pressure it needs to overcome.
  
  
• Flow rate: Most systems aim for 5–10x turnover per hour. A mixed reef with softies may lean lower, while SPS-heavy tanks benefit from more aggressive flow.
  
  
• Noise level: DC pumps are often quieter and include adjustable speed settings—perfect for setups in living spaces or offices.
  
  
• Reliability: Reef systems run 24/7, so durability matters. Look for a saltwater aquarium return pump with a solid warranty and proven track record.
  
  

Not sure what size or model fits your setup? Our team is happy to help match you with a pump that fits your tank volume, head pressure, and goals.

Expert Tips for Setting Up and Maintaining Return Pumps

• Size beyond flow rate — account for head pressure.
  Many hobbyists choose a pump based on GPH alone, but underestimate how vertical height and plumbing bends reduce flow. Check your total dynamic head (TDH) and consult performance charts from the manufacturer—not just the box rating.
  
• Use unions or quick-disconnects from the start.
  Return pumps need regular cleaning to prevent calcium buildup or clogged impellers. Hard-plumbing without unions makes removal a headache. Add them during setup to save yourself hours down the line.
  
• DC pumps offer more than quiet operation.
  Adjustable speed, feed modes, and built-in fail-safes are standard in most DC return pumps—making them ideal for modern reef systems. If your tank has variable needs or if you're running a controller like Apex or Hydros, DC is the smarter long-term investment.
  
• Plan for power loss scenarios.
  If your pump stops, your tank shouldn’t drain. Use a check valve or drill a siphon break to prevent back-siphoning from flooding your sump during outages. Bonus: Consider battery backup for tanks with high oxygen demand.
  

Don’t oversize unless your overflow can handle it.Bigger isn’t always better. An overpowered pump can outpace your overflow and cause noise or microbubble issues. Match your return pump’s flow rate to your overflow’s capacity after accounting for head loss.