Sucking Air on Pressure side of pump


New member
Sep 23, 2021
I didn't think this was possible but I seem to have an issue with my Chlorinator sucking air, and a lot of it! I noticed that I have a lot of air being returned into my pool, after investigating each device, I found a lot of rumbling air-type noise coming from my chlorinator. I noticed that if I turned it up to max the rumbling would go away and all bubbles would stop from coming into my pool. If I turn it back to 5 where I normally keep it or really anywhere below max it starts rumbling and blowing bubbles back into the pool. I thought maybe the lid was not on right and adjusted it several times, also thought maybe the chlorine tables may have gotten stuck in the in or out valve system and I did a quick cleaning and rearranged all the tabs. Still no change, no Bubbles on Max and tons or bubbles on any other setting. I did some research to see if this was a common issue and only found that what is happening is seemly impossible that if the chlorinator had a leak it should be squiring water not sucking air. My chlorinator is the last device before my outflow valve. Model # CL2002S.

Thanks for any help.


TFP Expert
LifeTime Supporter
May 3, 2007
Pleasanton, CA
Pool Size
Salt Water Generator
Welcome to the forum!

First, it would be helpful in you could fill out your signature with a description of your pool and equipment:

Chlorinators like that use a venturi to suck out the water/CL in the main vessel where the tabs reside. If the flow rate through the venturi is high enough, it can create a vacuum inside of the vessel and if the o-rings do not seal well enough, it will suck in air.

First inspect all of the o-rings to make sure they are not cracked anywhere.

Next, lube the o-rings with some pool lube to see if that helps.

Again, a detailed description of the plumbing setup and equipment would be helpful. A few pictures would not hurt either.

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
Texas, San Antonio/Marion, South-Central Area
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Welcome to TFP! :wave: Feel free to post some pics as well if it will help.

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