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Avoid air traps

In a gravity-fed system, hose routing is just as important as hose size.

Try to avoid high points, loops, bumps, or unnecessary up-and-down sections in the main line. These can trap air inside the hose. Trapped air interrupts the water column and reduces the already limited pressure of the system.

This video explains the concept well and shows why trapped air can become a problem: Gravity Fed Irrigation: Air Trap Explanation

A good routing principle is:

  1. The main hose from the container should go straight down.
  2. OpenValve should be placed in this downward line.
  3. After OpenValve, the main line should continue downward until it reaches the lowest practical point in the setup. On a balcony, this is usually the floor.
  4. From there, the main line can run horizontally to the plants.
  5. Avoid bumps and high points in the main line as much as possible.
  6. When branching from the main line to micro tubing, make the connections on the top side of the main hose whenever possible.

Connecting micro tubing on the top of the main line gives trapped air a path to escape. In contrast, side-facing or downward-facing connections can trap pockets of air inside the main line. If all branches are connected side-facing or downward-facing, the trapped air may have no practical way to leave the system, reducing the already limited performance of a gravity-fed setup.

tip

When routing the hose for a gravity-fed setup keep in mind: Air is lighter than water and always wants to rise up. Make sure the air always has a path to escape, either through the emitters, or through the mainline into the tank. If a highspot is unavoidable, use air release valves.