Choosing a Return Pump for Your Sump System

The return pump moves water from your sump back to the display tank, and choosing the right size matters for both flow and long-term reliability.

Turnover Rate

A common target is 5-10 times your total system volume per hour, though this can vary based on how much additional flow your powerheads (see our powerheads and wave makers guide) provide separately.

Accounting for Head Height

Pump output drops as water is pushed higher, so always check a pump’s performance curve at your actual head height, not just its maximum rated flow at zero height.

Reliability Over Raw Power

A dependable pump running below its maximum capacity is far better than an underpowered unit running at its limit constantly, which increases wear and failure risk.

Redundancy Planning

Consider keeping a spare pump on hand, since a return pump failure can quickly become a plumbing emergency if a sump isn’t set up correctly, discussed in our sump guide.