Loc-Line Check Valve

The Loc-Line Check Valve snaps into a 1/2" Loc-Line run and lets water flow one way only. On an aquarium return line it helps stop back-siphon, so when the pump shuts off for feeding or a power outage, your display is not quietly draining into the sump. Genuine Loc-Line, built from the same saltwater resistant acetal as the rest of the system, with a nitrile seal.

Why a Check Valve

Any return nozzle that sits below the waterline becomes a siphon the moment the pump stops. A sump sized for normal operation can overflow fast when the display starts draining backwards. A check valve in the return line blocks that reverse flow automatically, no float switches or drilled siphon breaks required. It is cheap insurance for AIO conversions, nano reefs, and any sump where headroom is tight.

How to Install

• Snap the valve into the 1/2" run between the pump side and the nozzle side. The flow arrow points toward the tank.
• Place it somewhere easy to reach: like every check valve, it should be inspected and cleaned periodically so the seal stays free of algae and detritus.
• Our Loc-Line Assembly Pliers make seating and separating the ball joints painless.
• Treat it as a backup, not a guarantee. Keep enough empty sump volume to absorb some backflow, because a fouled check valve can leak.

Specifications

Recommended Pairings

• Loc-Line 6-Segment Sections: build or extend the run
• Loc-Line 1/2" Nozzles: round, flare, spray bar, and 7 hole tips
• Loc-Line In-Line Valves: quarter turn manual flow control
• Loc-Line Assembly Pliers: the joint tool worth owning
• Shop all saltwater supplies

Frequently Asked Questions

Will this stop my sump from overflowing in a power outage? It blocks reverse flow through the return line, which is the main back-siphon path. Pair it with sensible sump headroom, since any check valve can weep if debris holds the seal open.

Does it restrict flow? A small amount, like any check valve. Most return pumps will not show a noticeable drop on a 1/2" line.

How often should I clean it? Pop it out and rinse during regular maintenance, every month or two on most systems. A clean seal is what keeps it trustworthy.

Does it fit the 3/4" system? This valve is for the 1/2" Loc-Line system only. For 3/4" runs, use a barbed or union-style check valve in the hard plumbing before the Loc-Line section.