How to Use a Venturi System Instead of a Blower on a Block Hot Tub Build

Recently, I received a comment from a subscriber asking about how to use a Venturi system instead of a blower on a concrete-built hot tub. They also wanted to know if I could make a video on this topic. I love getting requests like this because they’re both interesting and useful for anyone tackling a DIY hot tub build!

I’ve gone ahead and made the video, which you can check out below, but if you’re looking for a step-by-step written guide, keep reading!

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The Standard Setup for a Block or Concrete Hot Tub

Let’s start by understanding the typical setup of a concrete or block-built hot tub, often using a gunite body, jet pump, and air blower.

• The gunite body has a 1.5-inch airline at the top.
• There’s a 2-inch waterline at the bottom.
• A 2.5-inch pipe runs through the walls and into the hot tub.

Here’s how it works: Water is pumped through the 2-inch waterline by the jet pump and comes out through a 1-inch pipe that’s inside the larger 2.5-inch pipe, which directs it into the tub.

As water moves through, a small hole in the airline allows air to be drawn in through the blower line. The pressurized air mixes with the water via the Venturi effect, creating that bubbly, effervescent experience we all love in hot tubs.

The Venturi Setup Without a Blower

While I’m a fan of air blowers, I understand they’re not for everyone. The subscriber who requested this video wanted to avoid using one, so here’s how you can use a Venturi system instead.

In a Venturi setup, water moving quickly over a hole draws air into the hot tub jet. If you’re not using a blower, you can still get air into the lines by tweaking the system.

Step-by-Step Guide to Setting Up the Venturi System

1. T into the Airlines

First, you’ll need to T into the existing airlines and turn the airline vertically up along the ledge of the hot tub. On the level edge of the hot tub, you’ll place an air valve, which will look something like this:

This valve is manually adjusted and allows air to be drawn into the system via the Venturi effect when the jet pump is running.

2. Adding Multiple Air Valves

You’ll want more than just one air valve in your setup. For instance, if you have a square hot tub, I recommend placing one valve on each of the four sides. This setup will give you more flexibility and control over the amount of air being drawn into the jets.

3. Separate Air Systems for More Suction

Instead of connecting all the airlines together, I suggest creating separate systems. For example, if you have a 16-jet system, divide them into groups of four jets per side, each with its own air valve. This will provide better suction and performance for each set of jets.

This method ensures that the air is evenly distributed and doesn’t all get pulled from one side of the tub.

Installing a Venturi system can seem very complicated and difficult but hopefully after reading this article, you’ll know what you’re doing!

Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi

 

Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi