Both your fish and your plants rely on oxygen to stay alive. Most growers handle this with an airstone connected to an air pump, but that approach comes with a few real drawbacks: it draws power constantly, it requires you to buy an air pump, airstones, and tubing, and the stones themselves need regular cleaning to keep working. A venturi is a simple way to sidestep all three of those problems.

What Is a Venturi Aerator?

A venturi aerator is a fitting that raises the amount of dissolved oxygen in your water. Warmer water naturally holds less dissolved oxygen, and a venturi’s entire job is to boost that oxygen level without relying on an air pump at all.

How Does a Venturi Work?

Picture water entering the fitting on one end under pump pressure. It then gets forced through a narrowed section of pipe, where — thanks to the Bernoulli principle — the pressure drops. That narrowing speeds up the flow of water, and once the water clears the narrow section and the pipe widens again, the sudden expansion creates suction. Position an air tube at that exact point and the suction pulls air in, mixing it directly into the water stream.

How to Build Your Own Venturi

You can buy a venturi fitting ready-made, but putting one together yourself is straightforward. Install it in the line right after your pump, before the water reaches the rest of your system. Start with a 1-inch pipe that steps down to 3/4 inch, then drill a hole in the top of the 3/4-inch elbow and fit in a length of flexible PVC tubing cut at a 45-degree angle. Built at this size, the fitting can move roughly 900 gallons of water per hour.