Flush water from a CO2 tube using an aquarium pump

Hey all,

It’s winter, and I’m one of those unfortunate suckers with a shattered laser tube due to frozen water expanding inside.

I’ve got a replacement, but I’m not ready to install it yet until the weather warms up and I have a solution to prevent the same issues again.
I’ve considered anti-freeze, and I see there are pros and cons to it.
I’ve also seen a neat trick with an aquarium heater inside the water cooler, but I’m concerned it just won’t heat the system well enough to prevent freezing.

So, I had another idea! But much to my surprise I’m not finding information online about other people trying this out.

The short version is I want to set up an aquarium pump to automatically turn on for a few minutes after I turn off my laser cutter, to flush all the water out of the tube (or at least MOST of the water, enough so that frozen water won’t be able to damage it).
I have a design in mind for how to achieve this, and I have all the pieces already.

But here’s my question… before I waste my time, has anyone tried doing something like this before? Would a low powered aquarium air pump (I have a 5v usb air pump) be capable of flushing out the water from the tube?
Can anyone think of any downsides to this approach?

I can provide more details on my intended design if anyone wants to know.

And just in case anyone is wondering. I have considered backflow issues, so I’m getting 2 check valves for this plan. One to prevent water from the cooler flowing into the air pump, and one to prevent air flowing in the wrong direction back into the cooler.

If your tube is installed properly, the outlets are going ‘up’ to allow any air in the tube to be pushed out by the normal coolant flow.

It’s exactly opposite of what you want when you use air to push out the liquid…

You’d need a lot of pressure and flow to get all the water out… Can’t say I’ve heard of this, but it sounds like it reeks in problems.

Don’t know where you live, but how about something like this… good to -31F … I’m using it this winter…

If you live across the pond … this has an additive to make it non toxic.

Don’t use automotive antifreeze. It contains additives the allow the coolant to conduct more easily…

The hv has jumped to these coolants under some conditions… it makes anything the coolant touches have a hv potential …

Good luck


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Looks like neither of those products are available to me. I’m in Canada.
Perhaps the OMTech coolant will become available sometime in the next few months, which is fine since I’m not going to install the new laser tube until weather warms.

Do you have any other antifreeze recommendations? One of the reasons I decided not to go with that approach is because I wasn’t able to find a good, recommended product. Every antifreeze I’ve found which has been recommended for laser tubes has been either out of stock or not available in Canada.

Since I have the parts, I might experiment with flushing the water out anyway. I’ve seen one video of someone doing it with a more powerful compressor, seems like it wouldn’t hurt to try with a low power pump. If it doesn’t work I’ll know straight away.

Don’t know about the temperatures where you live, but I ran 50% mix of Propylene Glycol/distilled water in mine for over a year, but it’s only good down to about 15F. Pure form has a much lower freezing temperature, but is rather thick… the liters/min was cut by half with my 50% blend…

I’ve changed my coolant … might be easier to just remove the tube and ‘tilt’ it… That’s how I get the coolant out of mine… Most of these mounts seem to have good replacement alignment. I do it to mine and it’s still properly aligned… just a thought … remember you need the length in wires and coolant hoses to be able to ‘tilt’ it enough.

Is it something that can’t be shipped to Canada or is it just sold out? OMTech has the one I posted for $10 less USD, but they were sold out less than a week after I got the advertisement.

Let us know your course…

Good luck


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I’m on Vancouver Island, in BC. This year it got as low as -12C (10F), so it sounds like that mix wouldn’t have worked. This has been an exceptionally cold winter though.

The OMTech product isn’t available on Amazon or on their website.

Actually, as for the LS Coolflow, I had only assumed shipping from the UK would be expensive so I didn’t try, but it’s only £9. That’s probably a mistake on their website, but I’ll soon see if they will honor it :laughing:
If that arrives I’ll just use that.

I’m still gonna experiment with the pump and water though. I’m excited to try it :yum:

Thanks for the advice!

As you increase the glycol percentage, it goes down… That’s pretty chilly in any case.

I don’t know what you have, but my chiller is 6L and they sell it in 5L bottles… I’m sure it’d run ok with only 5, but I like to keep it near full.

Good luck


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I’ve used RV antifreeze for years without issue. This is the stuff you put in the drains of boats and RVs to winterize them. I don’t live in a cold climate but I think they are good to -50F.
I have seen posts about certain antifreeze compounds causing issues with the beam but over three different tubes have not had issues with this material 100% out of the container

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