How to build a CO2 blowout system for clogged lines?


Feb 22, 2020
Austin, TX
I've searched the depths of the Internet, and I cannot find instructions on how to build a CO2 blowout bag system. I hired a company a month ago to blow out my lines, and the tech's system was leaking to the point where he couldn't generate enough pressure to clear the lines. I have a full CO2 tank (from a reef aquarium), a regulator and an 80 PSI canvas flushing bag is arriving this week (Petersen 102-002...which was the highest PSI rating I could find), but I cannot find instructions for connecting the bag (3/4" hose thread) to the CO2 regulator (which uses a special gas thread in NA).

Anyone have details on building the hose system? Also, I just tried using 80 PSI of water in the cheap/rubber blowout bag Lowe's sells, and the clog isn't budging at all. I've read stories about potentially having an air lock, so any advice is appreciated! Also, in the CO2 threads/videos I have reviewed, most people are not using a regulator to blow out the lines. I've read horror stories about ruptured lines underground, so I wonder how companies (including the one I hired) are using straight CO2 tanks without a regulator.

Thanks again,

PS - I had all of the mosaic tile in our pool replaced this year, and the masonry team didn't bother covering the drains during the demolition process.


TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I would be really concerned about using a high pressure gas to remove what could be a cement clog. The biggest danger is at glue joints where a pressurized gas could easily cause enough expansion in the PVC to crack a glue joint. If it were leaf debris that’s one thing but the possibility of a cement like substance causing the clog is a whole different story.

Have you contacted a drain repair plumber as they have the experience and tools to do mechanical clearing (high pressure water driven cutting heads)? They can scope the line and determine exactly what the clog is and where it is located rather than trying to blindly blow it out.

A damaged buried pipe would be way more expensive to repair than hiring a pro with the right equipment.
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Silver Supporter
Aug 28, 2012
Houston, TX
X's 2 what Matt said - this comes down to the right tool for the right job...first locate where and what it is, then you will know how to deal w it.


TFP Expert
Mar 2, 2011
What line is clogged and how did someone determine that it was clogged?
How long has it been clogged?
Does anyone have any idea what is in the line?
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Well-known member
Mar 4, 2015
Sugar Land , TX


Feb 22, 2020
Austin, TX
I put the rubber blow bag on the lines again tonight. I ran the main drain line until the air bubbles were gone, and then I switched to the skimmer line. I created some back pressure using the diverter valve, and one of the old 1" glass mosaic tiles came up through the line. I'm sure there is more stuff in there, so I'll call around tomorrow to see if someone is available to blow the line with CO2. I bought one of the snake cameras from Amazon last weekend, but I had trouble getting it through the 90 deg corners.

Why do I suspect the line is partially blocked? The filter pressure gauge was running unusually low after the pool company primed the pump when they were here installing automated dosing equipment on that basin last week. The masonry crew didn't cover the skimmer box (lid was off) during the demolition/construction processes. I was able to get a piece of glass mosaic through the line tonight with water pressure. The pump is almost impossible to prime. Normally the pump is tricky to prime, but despite spending hours using the usual priming process/tricks, I cannot get it to prime. I was using and 80 PSI line tonight (gauge was at ~60 PSI during the blowout process), and I was getting some slow air bubbles and water flow...but nothing like the geyser you typically see when unclogging a blocked line. I'm going to remove the main drain cover and have the lines blown out, so I'll keep you posted. We are working on the slide catch pool, so the depth is only ~4'.