Siphon Valve 3/4"

The Siphon Valve 3/4" drains ebb-and-flow trays using pure physics - no timers, no motors, no solenoids. It suits growers who want reliable, hands-off flood drainage without adding electrical complexity to their system.

Ebb-and-flow irrigation depends entirely on how quickly a tray drains after flooding. Leave roots sitting in water for even a few extra minutes per cycle and you risk oxygen deprivation at the root zone. This valve solves that by using a siphon effect: once the water level climbs to your chosen trigger point, the valve activates and evacuates the tray rapidly and evenly.

Three adjustable water levels give you practical control over flood depth. Propagating cuttings? Set a shallow level so only the base of your cubes sits in solution. Larger plants in bigger pots benefit from a deeper flood to ensure the full root-ball gets contact with nutrients before drainage begins. Switching between levels takes seconds and requires no tools.

Fitting the valve to a 3/4" drain port is straightforward. It works with standard ebb-and-flow tables and grow racks that use this common drain size. Pair it with a submersible pump on a mechanical timer and you have a complete, low-tech flood-and-drain loop. For tray-based growing on G-Tools Bonanza or similar rack systems, this valve slots neatly into the existing drain fitting.

Cleaning is simple. The design limits the number of tight internal passages where algae and root debris typically accumulate. Disassemble the components, rinse under tap water, and reassemble. UV-resistant, nutrient-proof plastic means the body will not degrade or discolour under repeated chemical exposure over multiple growing seasons.

Grower’s Note: With ebb-and-flow systems, drainage speed matters as much as flood duration. A slow drain keeps roots anaerobic longer than necessary. Use this valve's siphon action to keep each flood cycle short and decisive - typically 15 to 30 minutes total flood-and-drain time works well for most crops in a standard grow tray setup. Always check the drain line below the valve is clear and has a slight fall so the siphon can complete its cycle without air locks.

Priced at £58, with free UK delivery.