Co2 regulator issue has me stumped

[aquagardenlivingart]

So, this is my set up.
Here is my check valve set up and a nilocg co2 reactor plumbed into the fluval fx6 line.

I have a brass check valve attached to a shut off valve. Cracking pressure is 1/3 psi.
I'm not sure why but I keep getting water in my matheson fm-1000 flowmeter and clippard solenoid. I can't figure out where its coming from or how its getting in. I have three of these matheson fm-1000 flowmeters that I picked up on ebay cheap. I keep have to switch them out and take everything apart, clean it, dry it, and reassemble to switch back the next time. I've pulled the check valve off and replaced it. I've blown in it to verify that it is only working one way. Seems to be good. The only thing I can think of is maybe it is allowing small amounts of water through in certain situations and its accumulating and getting sucked back through the lines. I do see some moisture droplets on the section of line between the flowmeter and the check valve after a while. My only thoughts on troubleshooting is to add a second check valve like this one that has a 1 psi cracking pressure and viton seals directly after my flowmeter.
I would add it here between my 90 and the barb.
I will also replace the 1/3 psi check valve closer to the reactor with another 1 psi check valve with viton seals. Am I missing something? Any other tips to troubleshoot this issue? Any help is much appreciated. @Bettatail helped me with this set up at couple years ago. Its hard to find people knowledgeable on this. Any help is greatly appreciated.

 

[Naturescapes_Rocco]

I'd add two cheap inline check valves asap. You definitely don't want water in there!

Add two, with a clear piece of tubing between them, so that way if the first one fails, you can see it before it reaches the second.

Check valves are maintenance parts; they need to be replaced over overtime. I replaced mine at least once a year.

 

[aquagardenlivingart]

I'd add two cheap inline check valves asap. You definitely don't want water in there!

Add two, with a clear piece of tubing between them, so that way if the first one fails, you can see it before it reaches the second.

Check valves are maintenance parts; they need to be replaced over overtime. I replaced mine at least once a year.

Thanks. I happen to have a handful of cheap plastic ones on hand. I just added two as you suggest. My co2 was on when I went to add them and the line was dry. I turned it off and when I checked the line there was an inch or so of water in the line at the brass check valve on the side it shouldn't be. So water is definitely getting past that check valve. Ive ordered two new brass ones. One to add screwed into fittings right at my flowmeter and one to replace the brass one that is leaking at the shut off valve close to my reactor. I think I'll leave the cheap plastic ones on inline as well. Hopefully that solves the issue.

 

[Koan]

inline check valves asap

These instead

Journal Post in thread 'Fishstery's Garden/Nature style hybrid'

Mar 3, 2026

push-in style check valves that also then serve as an easy disconnect

These are bulletproof

Mur-lok Inline Check Valve 1/4" x 1/4" Push Connect

Mur-lok RO fittings are the only RO fittings that feature dual EPDM O-rings to ensure a straight leak free fit. We believe GA Murdock Mur-lok fittings to be the best so strongly that we use them virtually exclusively on each of our BulkReefSupply.com reverse osmosis units and BRS media reactors...

www.bulkreefsupply.com

• Koan

• 

 

[Bettatail]

as rocco suggest, use inline check valves and if water back flow, you can see the water goes up into the hose.
during light/power off period the water may sip back up the hose but should not pass the check valve.

and, it is a rare turquoise clippard solenoid that I never own one....
This solenoid is a 3 way. To convert it to a 2 way, use a 10-32 screw with sealant or nylon washer to seal the top port, other wise once the solenoid powers off, the pressure inside flowmeter instantly drop to 0 psig and water may rush back up the hose.

 

[Bettatail]

one more thought, about moisture gets into the flowmeter.

first, the 3 way solenoid release and create an opening to the outside humid air while the power is off, so overtime the flow meter have water inside. seal the top port of the solenoid with take care of this.

second, It is a possible but not common problem. I see that you have a 20lb co2 tank, not the 5lb that most people use, a size of this co2 tank the refilling process sometimes is to fill with dry ice instead of liquid co2 refilling, according to your local refilling station. The dry ice method may have more chance of water contamination problem and you can see the moisture on the glass tube, but this is less than likely because the water inside the co2 tank will go away fairly quick once you start using the co2 tank.