Collection: Overflows

Getting Water to the Sump

An overflow is what sets your display's water level and feeds the sump. Get it wrong and you get a noisy siphon, a fluctuating water line, or — worst case — a flood when the siphon breaks and the return pump keeps running.

Hang-On or External

• Hang-on overflow boxes — for drilled-free tanks, rated by flow so you match the box to your return pump rather than the tank size.
• External overflow kits — for drilled tanks, mounting outside the display to free up interior space.
• Filter sock holders — hang-on holders that add mechanical filtration where there's no built-in sock chamber.

Size the overflow above your return pump's actual output, not at it, so the box never becomes the bottleneck. Hang-on boxes rely on a maintained siphon — a siphon-break alarm or an aqualifter is worth having. Larger overflows ship at actual freight cost. Questions? Email sales@jlaquatics.com.