Newbie to pressurized CO2 system noticed unusual water back flow problem

[ortegafever]

Hi Veterans,

Recently i brought a brand new 3L CO2 tank with electric solenoid. After setting it up and monitoring for 2 days i noticed a strange water back flow problem.

Let me describe my set up first:

Solenoid output --> Check Valve (100% correct direction) --> Glass Diffuser (with bubble counter built-in)

I am using silicone airline tubing currently as the transparent CO2 tubing are sold out at the LFS, i brought the CO2 system from.
I had made sure there is no water in the tubing and diffuser before connecting them up and placing the diffuser into the water. The solenoid is managed by a timer which also controls my light.
The next day, i noticed that when the solenoid is off, water starts to enter the glass diffuser. At first i thought this is normal as the diffuser has a built-in bubble counter which needs water to function. (There is no opening on the diffuser which allows me to pour in water myself for the bubble counter.) But then later on, i notice the water starts to black flow into my CO2 tubing as well and is slowly making its way to my check valve.
Initially i thought my check valve was faulty hence i changed one. (Both was brand new) However, with this second check valve, the problem still persist which worries me.
My question is,

1.) Is this normal? I hope someone who had faced the same problem can clarify with me.

2.) Is it because i am using a plastic check valve? Would a brass one perform better?

3.) Or is my glass diffuser faulty? I can see one hairline marking on its body but does not seem like a crack. More like a scratch.

For now i have removed the tubing on the solenoid side and placed that end in a bucket. Wanted to see if the water will eventually pass the check valve and leaks out or will it just stops at the check valve's output side.

I am concern that water will get into my solenoid if i continue using this setup hence hope any veterans here can enlighten me. Million thanks in advance!

Have attached picture of my diffuser and check valve for more details.

42d0_1.jpgANS Spiro 3000 Diffuser.jpg

[Shadow]

back flow is normal that why you need check valve but those plastic check valve in your picture not really work properly especially against air. It should work better once water reach it, use more that one check valve would be better. Brass type is better, IMO.

[felix_fx2]

That plastic check value, use 2 at least.
I have used the same one and the slow backflow sometimes do go past the 1st one.

Better safe then sorry

[AQMS]

I agree,use at least two check valve and get a better quality one preferably the brass valve.
I encounter the same problem when i first start this hobby.
Its all about learning and sharing.

[wongce]

i had back flow problems when i use the same check valve you are using, i switched to brass/stainless steel type x 2 after that, no issue so far...

[5stars]

Yup, that kind of check valve is not very good. There is another kind of plastic check valve that works really well. It looks like the one you are using, but the tip of the rubber inside the valve is rounded. Like the other bros mentioned, you should use at least 2 check valves, because even the most expensive check valve can fail.

[ortegafever]

Thanks for the sharing and advices bros! I'm glad to hear that it's a normal phenomena.

My experiment result matched what you guys had said (Not that i don't believe, just sharing):
> This morning i observed that the water had reached about 1cm distance from the check valve's output.
> 9.5 hours later, the water can be seen bulging out at the inside of the check valve's output tip, but not yet entered the check valve.
> 9 hours later (currently as i am typing), 1/4 of the check valve is filled with water.
> Previous day after i switched off the solenoid, the water took about 18 hours to travel into the diffuser (totally empty of water) and along the tubing (about 1.2m long) to the point, 1cm away from the check valve's output.

My conclusion: If i on the solenoid for 8 hours per day, 16 hours later till the next cycle begins, the water should not have entered the check valve yet. So by then, when the cycle begins, the CO2 will push the water out of the tubing. Which means 1 check valve with a 16 hours gap is considered safe. But to be safer than sorry, i will use 2 check valves as advised. A few dollars for some check valves is nothing compared to buying a new solenoid..
Will definitely try the brass check valves, using them seems more "pro"

[ortegafever]

By the way, is the check valve with water inside still useable?

[legolandhere]

it should be still usable. i have 2 , one before the bubble counter and 1 after.

[ortegafever]

it should be still usable. i have 2 , one before the bubble counter and 1 after.

i can only place them after the solenoid as my bubble counter is integrated in the diffuser.
just got 2 metal check valves, going to use them after i can get my hands on some transparent co2 tubing.

[legolandhere]

That should be alright


Sent from my iPad 4

[chang]

Hi Veterans,

Recently i brought a brand new 3L CO2 tank with electric solenoid. After setting it up and monitoring for 2 days i noticed a strange water back flow problem.

Let me describe my set up first:

Solenoid output --> Check Valve (100% correct direction) --> Glass Diffuser (with bubble counter built-in)

I am using silicone airline tubing currently as the transparent CO2 tubing are sold out at the LFS, i brought the CO2 system from.
I had made sure there is no water in the tubing and diffuser before connecting them up and placing the diffuser into the water. The solenoid is managed by a timer which also controls my light.
The next day, i noticed that when the solenoid is off, water starts to enter the glass diffuser. At first i thought this is normal as the diffuser has a built-in bubble counter which needs water to function. (There is no opening on the diffuser which allows me to pour in water myself for the bubble counter.) But then later on, i notice the water starts to black flow into my CO2 tubing as well and is slowly making its way to my check valve.
Initially i thought my check valve was faulty hence i changed one. (Both was brand new) However, with this second check valve, the problem still persist which worries me.
My question is,

1.) Is this normal? I hope someone who had faced the same problem can clarify with me.

2.) Is it because i am using a plastic check valve? Would a brass one perform better?

3.) Or is my glass diffuser faulty? I can see one hairline marking on its body but does not seem like a crack. More like a scratch.

For now i have removed the tubing on the solenoid side and placed that end in a bucket. Wanted to see if the water will eventually pass the check valve and leaks out or will it just stops at the check valve's output side.

I am concern that water will get into my solenoid if i continue using this setup hence hope any veterans here can enlighten me. Million thanks in advance!

Have attached picture of my diffuser and check valve for more details.

42d0_1.jpgANS Spiro 3000 Diffuser.jpg

Bro,just to share my experience wit the chk valve YOU posted..can cause co2 leakage

edit: please refrain from using sms lingo. You can read the rules further from the link provided after this SMS and IM Lingo Rules

[ortegafever]

Bro,just to share my experience wit the chk valve u posted..can cause co2 leakage

Thanks for the sharing. I have changed to metal check valves like these shown below, already.
Will continue monitoring for abnormality. Pray none...

Brass check valve.png

[felix_fx2]

Thanks for the sharing. I have changed to metal check valves like these shown below, already.
Will continue monitoring for abnormality. Pray none...

Brass check valve.png

I have a surprise for you. I am using that plastic check valve as my 1st check valve (not 2nd)
very easily will leak air when its not closed and the seal become not good, didn't like the metal ones as i didn't have a clue what is going on inside.

[ortegafever]

I have a surprise for you. I am using that plastic check valve as my 1st check valve (not 2nd)
very easily will leak air when its not closed and the seal become not good, didn't like the metal ones as i didn't have a clue what is going on inside.

I'm confused. So are you still using the plastic check valve currently? Are you not concerned by the air leakage and the seal being not good?

Yea, the metal ones are opaque so cannot see inside. Plus the way it is constructed, i can say its practically indestructible unless you use a power saw to saw it open

My observation for day 1 the metal check valves been in full operation, 5 hours after the solenoid is off, i can say zero observable back flow. Now water cannot even enter the diffuser to fill up the space created when co2 entered the diffuser. Now i cannot determine whether it is the metal check valve or the polyurethane tubing that helps as i changed both at the same time Well unless someone is using plastic check valves with polyurethane tubing combination...

@Felix: i think you should consider using the metal ones, they are perfect for the moment

[tawauboy]

there should be some backflow due to CO2 being absorbed by the water.
in addition to using multiple check valves, you can use a longer tube length (ensure non-CO2 permeable tube) or add another empty bubble counter near the solenoid valve output. these methods will ensure that water will not enter the valve.

[5stars]

I'm confused. So are you still using the plastic check valve currently? Are you not concerned by the air leakage and the seal being not good?

Yea, the metal ones are opaque so cannot see inside. Plus the way it is constructed, i can say its practically indestructible unless you use a power saw to saw it open

My observation for day 1 the metal check valves been in full operation, 5 hours after the solenoid is off, i can say zero observable back flow. Now water cannot even enter the diffuser to fill up the space created when co2 entered the diffuser. Now i cannot determine whether it is the metal check valve or the polyurethane tubing that helps as i changed both at the same time Well unless someone is using plastic check valves with polyurethane tubing combination...

@Felix: i think you should consider using the metal ones, they are perfect for the moment

When I just started using pressurized CO2, I bought two of those metal ones from Nanyang Seaview. However, when I tried one, it allowed a bit of water to leak through (I used multimple check valves, so that was not a huge issue), and after a few months it, it actually cracked! (Not as indestructible as it appears to be)

As I have stated in another thread, it seems like those slightly more expensive check valves such as 'spring stop check valve' and 'double stop check valve' do not actually perform well as expected, especially if the backflow pressure is very high. Brass check valves seem to get a lot of positive feedback, but they so much more expensive than the much cheaper plastic check valves that do as good a job. Do take note that I am not refering to the plastic check valve shown in Post #1, which are awful and leaky, but the other kind of clear check valve with round rubber inside.

[ortegafever]

there should be some backflow due to CO2 being absorbed by the water.
in addition to using multiple check valves, you can use a longer tube length (ensure non-CO2 permeable tube) or add another empty bubble counter near the solenoid valve output. these methods will ensure that water will not enter the valve.

Hmmm, my polyurethane tubing is about 1m long (from diffuser to solenoid's output).
Second day of observation, again 5 hours after solenoid is off, no water back flow into the tubing. I am satisfied
Actually even if there is back flow into the tubing, i just want to be sure that in 18 hours time the water will never reach the first check valve (i used two), which also means my solenoid will be safe..
Not going to touch the setup for now since it's working finely. It's a painful process to disconnect the brass check valve from the tubing, they are fitted so tightly.

[ortegafever]

When I just started using pressurized CO2, I bought two of those metal ones from Nanyang Seaview. However, when I tried one, it allowed a bit of water to leak through (I used multimple check valves, so that was not a huge issue), and after a few months it, it actually cracked! (Not as indestructible as it appears to be)

As I have stated in another thread, it seems like those slightly more expensive check valves such as 'spring stop check valve' and 'double stop check valve' do not actually perform well as expected, especially if the backflow pressure is very high. Brass check valves seem to get a lot of positive feedback, but they so much more expensive than the much cheaper plastic check valves that do as good a job. Do take note that I am not refering to the plastic check valve shown in Post #1, which are awful and leaky, but the other kind of clear check valve with round rubber inside.

I'm surprised that it cracked! You must have godly strength..Though my friend did broke a plastic one.

Thanks for the info on those "special" check valves. I brought my brass check valve at $3.50 each. The plastic ones are $1.50 each if i remember correctly. I don't mind the $2 extra if it can last longer and perform better.

I think you meant these: DSC02062.jpg

[Shadow]

It's a painful process to disconnect the brass check valve from the tubing, they are fitted so tightly.

Normally what I did is cut the tube