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On The Job Site with Jen #1: How to Clean a Hot Tub or Spa Ozone Injector

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Many spas and hot tubs have an ozone generator either factory-installed or installed after purchase.  In most cases, there is also a component that is critical to getting ozone INTO the spa water – an injector.  Mazzei Injectors are the most efficient spa injectors on the market today.  With more mass transfer of ozone into water, ozone is better able to kill viruses, bacteria, oils and other organics, as well as control metal.

From time to time, especially in areas with hard water, a hot tub injector gets clogged.  Calcium is a common culprit.  When ozone is first introduced to spa water it gets to work fast.  You may notice within the first 24-48 hours the spa water gets cloudy.  THIS IS GOOD.  This is ozone attracting little, invisible particles together so the filter can finally remove them; this process is called micro-flocculation.

In this 24-48 initial period, you are now able to see the particles growing, hence the cloudy appearance (you couldn’t see it before; too tiny).  DO NOT SHOCK during this process – it will repeat this cycle until the metals and contaminants are removed in the filter.  CLEAN THE FILTER, clean the filter, clean the filter.

During the micro-flocculation process, and sometimes just over a period of time, bubbles will cease in the spa where the ozone comes out (typically one jet).  There are two main causes of bubbles stopping – the check valve failed, or the injector’s clogged.

If you suspect the injector is clogged, here’s how to unclog it:


  • 1 paperclip, straightened (or tool similar)
  • 1 cup or small dish to hold little injector pieces so you don’t lose them


1.  Turn off power to spa!    First, turn power off!

2. Open spa panel and locate the Mazzei Injector.  In some cases, there will be no injector or there will be a knock-off brand. 

3.  Once the Mazzei Injector has been located and the clear PVC Ozone Supply Tubing is clear of water (that’s right; there should be no water in this line), turn the spa back on.  If there is water in the line, water will drain from the spa.  Do not perform the Injector Cleaning at this time – call us first at 888.242.0111 or email for help at help@loveyourhottub.com.

4.  When the spa is turned on (which is is not right now) and in filtration mode, the injector’s job is to create suction and suck ozone out of the ozone generator and mix it into the spa water.  Therefore, when you remove the clear PVC Ozone Supply Tubing from the injector (again, when spa circulation is turned on) and place your finger over the injector inlet (see injector inlet picture below), there should be a slight sucking on your finger tip.  If the injector is clogged, there will be no suction (nor will there be bubbles).

5.  If there is no water in the PVC Ozone Supply Tubing, and the spa is now turned back on and you have determined there is flow, CAREFULLY unscrew the injector cap – sometimes there is an O-ring or a spring and ball, so use caution  not to drop these little parts!  Use a cup or small dish to hold.


6.  Using the unbent paperclip, GENTLY poke the throat of the injector (you can scar the injector, affecting your bubbles).  Calcium is the main contributor of clogging and will quickly be freed, creating suction immediately.  Bubbles should now appear in the hot tub


7.  For extra cleaning, take the Ozone Supply Tubing at the check valve and, while the spa filtration is running, suck ¼ cup of white vinegar through the injector.  This will further dissolve minerals, metals and chemicals lurking inside the injector.

8.  Once you see bubbles in the spa water again, put the injector back together.  Good Job!  If you live in an area with high metal and/or mineral content, expect the water to become cloudy-looking in the first 24-48 hours.  Do not shock the water (which most people do).  This is a good, natural process that shows ozone is cleaning your spa water.  Clean your filter.  Once your water is clean, you will notice the water is easy to balance (like it was when you first got your hot tub…remember that?).

  What great ozone-air bubbles look like in a hot tub

9.  Which way the injector is installed is important.  In portable hot tubs with ozone, ensure the injector suction port is pointing UP.  If it were pointing down, during normal filtration cycles, the injector drains a little, and you don’t want water draining backwards into ozonator; you want it to drain into the hot tub water line.  If you have no choice, and your injector suction port has to face down (facing outward is okay, parallel to the floor), we recommend changing your ozone check valve annually and/or adding a second ozone check valve.

10.  If cleaning the injector didn’t work (i.e. still no bubbles), your spa may not have enough flow or power to create suction.  There are many injector sizes, so we can help determine if there’s a better injector for your spa application