[Matthew RJ]

I had my CO2 off for a while. I didn't have time to get it refilled, had to leave my tank at a shop over the weekend. It's time to hook it back up before the plants start to really suffer.

I think there's water in the line from the check valve into the diffuser. When I turned on the gas, water from the bubble counter went into the line, pressure built, and the tube blew off the check valve.

Do I drain water out of the filter line, take off the tube at both ends, and blow it out with an air pump?

 

[kevmo911]

You'll probably want a new check valve. If it's metal, it's possible that corrosion sealed it, due to the constant contact with water, which might explain why the tubing blew off. However, under normal pressure, no lines should blow off. I've had it happen at around 50 psi, but that's higher than there's generally any good reason to have it at. Is it possible your tubing isn't sized correctly?

Regardless, if things were working fine before, I'd probably just get a new check valve and not look into replacing tubing or tweaking regulator working pressure first. If it happens again, I'd look into it. But if the check valve you're using is the common, "stainless steel" (they're not really) shiny metal type, often with an arrow on it, they're garbage, and if you're going to use them, I'd suggest at least two in series. I mention them because they're very common, and prone to early failure.

Also, regular contact with water will hasten the demise of any check valve, and they will *all* fail eventually, regardless of water contact. So it's not a bad idea to have spares.

As for blowing the water out, I'd try to drain it, but wouldn't worry much about it if I couldn't. It should push itself out once a new check valve is in place. Though I might turn the pressure down a bit just until the water's out. Or not, depending on how patient I was feeling.

 

[Matthew RJ]

You're right on my check valve. Do you have any suggestions on replacing with a better valve?

 

[jeffkrol]

You're right on my check valve. Do you have any suggestions on replacing with a better valve?

This type worked fine for me for a few years.
One got "sticky" but not corroded.

Others like the disc type...supposedly you can get samples for free somewhere

 

[lksdrinker]

I had my CO2 off for a while. I didn't have time to get it refilled, had to leave my tank at a shop over the weekend. It's time to hook it back up before the plants start to really suffer.

I think there's water in the line from the check valve into the diffuser. When I turned on the gas, water from the bubble counter went into the line, pressure built, and the tube blew off the check valve.

Do I drain water out of the filter line, take off the tube at both ends, and blow it out with an air pump?

Something doesn't make sense here. It is quite common for water to siphon out of the tank into a co2 line. Once the co2 is back on the pressure should push the water out of the way. No big deal. Its not common for the co2 pressure to force water from your bubble counter into the line and then build up pressure. There should be nothing restricting the flow from the bubble counter to the tank. Did you possibly remove the check valve and install it backwards?

 

[jeffkrol]

Something doesn't make sense here. It is quite common for water to siphon out of the tank into a co2 line. Once the co2 is back on the pressure should push the water out of the way. No big deal. Its not common for the co2 pressure to force water from your bubble counter into the line and then build up pressure. There should be nothing restricting the flow from the bubble counter to the tank. Did you possibly remove the check valve and install it backwards?

In-line atomizers actually create a lot of back pressure. Anytime (well a soon anytime) , even w/ the solenoid off, if I disconnect from the check to bubble counter, the remaining pressure blows all the water out of the bc.
Granted after time this pressure bleeds down. One of the reasons you need 30psi or so is to overcome this "wall"..
When I wrote about the sticky check valve above .. this happened quite easily..
Hard to explain, sort of.

 

[sohankpatel]

This type worked fine for me for a few years.
One got "sticky" but not corroded.

Others like the disc type...supposedly you can get samples for free somewhere

You're right on my check valve. Do you have any suggestions on replacing with a better valve?

Go to Ark-plas.com and make an account. Request samples of the Viton/Kynar valves. They are amazing valves, I have run the same 2 for 6 months and there is no changing how they operate. I check them once a month and they seem the same as the day I got them. The stainless steel ones suck, mine didn't last, even though it got good amazon reviews. Co2 is pretty nasty stuff, I had some silicone tubing inline, and it slowly turned opaque and then got stiff after a couple months. I don't like the plastic valves, because the same thing happens on the inside, they get stiff and dont seal.

 

[lksdrinker]

In-line atomizers actually create a lot of back pressure. Anytime (well a soon anytime) , even w/ the solenoid off, if I disconnect from the check to bubble counter, the remaining pressure blows all the water out of the bc.
Granted after time this pressure bleeds down. One of the reasons you need 30psi or so is to overcome this "wall"..
When I wrote about the sticky check valve above .. this happened quite easily..
Hard to explain, sort of.

Well they dont "create" pressure out of nothing though. I can see how pressure might build up in a line because of the diffuser creating a "blockage" so to say. I guess I'd have to see the setup and know where everything is in line and in relation to one another to really comment further.

 

[jeffkrol]

Well they dont "create" pressure out of nothing though. I can see how pressure might build up in a line because of the diffuser creating a "blockage" so to say. I guess I'd have to see the setup and know where everything is in line and in relation to one another to really comment further.

funny this topic came up now.. i'm still fighting w/ one of my "recommended" check valves.. That "Ista" is basically a silicone cone that fits tight inside a plastic "seat".
Small SS spring holds it in
"check"..
It still sticks..
So last night, since my bubble rate became erratic I shut the CO2 off (so it didn't kick on in the morning) and let it "bleed" out the pressure that remained "after" it stuck shut..
Popping the hose this AM "still" had a wee bit of back pressure in the line from drop to check. Not enough to blow the bc water out.. but a teeny "hiss"...

Still can't understand how it can stick. Si to plastic, after a good cleaning..
Point is even w/ "backwash" the valve could seal and create the
"pressurized" situation..

But you need very specific conditions..
In other words the atomizer is not really an "open" port...it has some
pressure retaining ability. At least for a short time..

 

[Matthew RJ]

Was at my LFS, and they had nothing. One clerk was going to sell me a generic check valve, but a colleague said it wouldn't handle pressure. His suggestion was to go to hardware / autoshop. I was going to do that tomorrow.

Thanks for the reference to Ark-plas.com -and I'm open to any other tips or guidance. I never considered check valve before.

 

[kevmo911]

1/8" Kynar® Standard Check Valve | U.S. Plastic Corp.
1/8" x 1.40"L Hose Polypropylene Mini Check Valve | U.S. Plastic Corp.

Either of those would be decent, and you can get a good handful for the price.

 

[Matthew RJ]

Does anyone use the green leaf atomic check valve?

 

[kevmo911]

Does anyone use the green leaf atomic check valve?

I would really love to recommend a high-quality check valve. However, my experience with the Swagelok 1/3 psi SS valves is that they don't last much, if any, longer than a decent-quality polypropylene valve, when used for our purposes. Wet CO2 is apparently very corrosive. I'm sure that some people have excellent reviews of the GLA valves, as do people for the Swagelok, Parker, Ham-Let, and other clone industrial pneumatic check valves, but I don't think there's a significant benefit to spending a lot on a check valve. However, everyone has opinions drawn from different experiences.

 

[Matthew RJ]

Thanks for all the replies & suggestions. I'm still having trouble finding one I can get my hands on - I'm in Canada, so shipping becomes a problem.

On a local fish forum someone posted a link to amazon.ca. Would these work?
https://www.amazon.ca/Uxcell-8-Piece-Plastic-Aquarium-Diffuser/dp/B00JQ9WSDI/ref=sr_1_1?s=pet-supplies&ie=UTF8&qid=1461324102&sr=1-1&keywords=aquarium+check+valve+co2

 

[jeffkrol]

Thanks for all the replies & suggestions. I'm still having trouble finding one I can get my hands on - I'm in Canada, so shipping becomes a problem.

On a local fish forum someone posted a link to amazon.ca. Would these work?
https://www.amazon.ca/Uxcell-8-Piec...4102&sr=1-1&keywords=aquarium+check+valve+co2

My experience is most of those "type" are pretty worthless..I do have a "tetra" branded one that actually seems to work though..
Maybe w/ 6 in a row....

Check automotive supply stores. I do know they have some sizes...

Also check MettleAir at freak bay canada..
or here:

https://www.amazon.ca/Viton-Non-Ret...id=1461326266&sr=8-1&keywords=mettleair+check

 

[Matthew RJ]

One more dumb question - what's the size of the tubing? 1/8 - 1/8?

 

[kevmo911]

Well, 1/8" ID and 1/4" OD is standard-ish, but if you bought it from a LFS, the ID is probably larger. Is the tubing floppy and squishy? If not, it's probably 1/8 ID. Either way, 1/4 by 1/8 is your best bet.

 

[JohnsTank]

Just to follow up, after running the Co2 for a while, the water was forced out. I had to disconnect the Co2 from the diffuser today and there was a distinct popping noise when I removed it so it is clearly under pressure.

 

[klibs]

https://www.amazon.com/Jardin-Plast...8&qid=1477660441&sr=8-28&keywords=check+valve

I use two of those on my tube and they work great. I got a few that were stuck but the ones that work fine are great (just blow through them to make sure they work first)

I also just use standard airline tubing you can get at home depot or any other store for a few bucks. some people frown upon this but it has always worked just fine for me.