Need to learn about pressure when it comes to CO2

Attached is rough photo of my co2 setup. I have a 125-gallon freshwater planted aquarium. 2 weeks ago, I got a refill to my co2 tank at the LFS. The 3 refills before that last 6-9 months each. Besides the first few days, ever since using this new tank I have been seeing 1 bubble per 3 or 4 seconds. Thinking I had gotten a bad tank or messed something up on reinstall, I took it back to the LFS (with my regulator connection) to get it tested. "Point A" is where I disconnected and took the rest to the LFS for testing. At the LFS, the bubble counter worked totally normal and we could regulate many variations of BPS. Yet I had the same issue when I reinstalled back at home again.

I've been running co2 for a decent amount of time now, so I did all the checks and balances that have solved issues in the past for me: soapy water on every connection, re-taped all the threaded connections, re-tightened all connections, moved the diffuser closer to the surface, and confirmed all gages are fully wide open.

I know there is some science behind tank co2 pressure, the pressure from the depth of water, etc. I'm trying to figure out if that may be the cause, and learn more about that. Or do I have a bad check valve? (the valve has been there on multiple tanks though)

 

Bad check valve or clogged up diffuser is probably what's causing the slow rate of release. I typically use reactors to avoid having to worry about bad diffusers or cleaning diffusers.
I would replace the check valve and diffuser and check for leaks in the tubing / connections going to and from both the check valve and diffuser.

 

Bad check valve or clogged up diffuser is probably what's causing the slow rate of release. I typically use reactors to avoid having to worry about bad diffusers or cleaning diffusers.
I would replace the check valve and diffuser and check for leaks in the tubing / connections going to and from both the check valve and diffuser.

The diffuser is practically brand new and completely white, so I'll see about the check valve first. Thank you!

 

The diffuser is practically brand new and completely white, so I'll see about the check valve first. Thank you!

Your working pressure might be too low to force CO2 through the diffuser. It used to happen to me all the time - I had a cheap regulator that couldn't get past 30psi and the diffuser was so restrictive 30psi wouldn't allow any gas through.

Sounds to me like the check valve might be your culprit though. I have also had check valve stick shut and wouldn't allow CO2 to flow.

 

Your working pressure might be too low to force CO2 through the diffuser. It used to happen to me all the time - I had a cheap regulator that couldn't get past 30psi and the diffuser was so restrictive 30psi wouldn't allow any gas through.

Sounds to me like the check valve might be your culprit though. I have also had check valve stick shut and wouldn't allow CO2 to flow.

I have tried cleaning the diffusers with bleach and removing the check valves. Still no bubbles come out of the 2 different ceramic diffusers I had on hand. I bought a $5 fluval diffuser and that worked, so I know co2 is getting through. But the diffuser is predictably bad and produces large bubbles that quickly rise to the surface and disperse.

Inline co2 are not an option for me- at least no good option that I've found for the fx6 webbed tubing.

What's frustrating is that I had no issues with my setup whatsoever before replacing the co2 tank most recently. It's like once I got this new co2 tank, that's when everything started going to . But I've had the tank tested and it's still full- or at least has plenty of liquidated co2 left. Before this tank though I had one ceramic diffuser with a check valve and it worked for 2 co2 tanks before that which was about 1.5 years in total with no issues

 

are the diffusers you are using from the same brand?
i had the same problem with diffuser before. diffuser was brand new but even when i fully opened the value, the bubbles were going at a max of abt 8 bubbles per sec.
checked everthing still the same. finally realised was the diffuser that is restricting the max. released CO2. changed the diffuser to another brand and CO2 was gushing out.
i had a metal diffuser that i can change the ceramic disc when its dirty. just yesterday i changed a new one, even fully opened no bubble was coming out.
then changed to another new pc and it worked fine. even within the same brand there is issue. thing is i already bought like 10 ceramic disc. so will finish using then and then will change the whole diffuser for a more consistent one.
i think some brand the diffuser was way less porous and needs pressure to work.

 

I would strongly recommend trying to sort out a reactor to use with the filter. I understand the ribbed tubing makes it more challenging, but with a reactor you never run into these sort of issues.

My working pressure is 10psi using a reactor, and I have not had 1 single issue in the past 6-7 years of using various DIY reactors.

If not, keep trying out new diffusers / brands of diffusers until you can get it sorted out.

 

I would strongly recommend trying to sort out a reactor to use with the filter. I understand the ribbed tubing makes it more challenging, but with a reactor you never run into these sort of issues.

My working pressure is 10psi using a reactor, and I have not had 1 single issue in the past 6-7 years of using various DIY reactors.

If not, keep trying out new diffusers / brands of diffusers until you can get it sorted out.

Hmmm are there any good tutorials or recommendations on that? I haven't been able to find any online yet but I'll keep looking even if it is diy. I had a reactor when I had my last, smaller, filter and it was amazing I agree. Never had any issue with that reactor.

 

Hmmm are there any good tutorials or recommendations on that? I haven't been able to find any online yet but I'll keep looking even if it is diy. I had a reactor when I had my last, smaller, filter and it was amazing I agree. Never had any issue with that reactor.

Not that I know of. One of the reasons I don't use the Fluval filters is their strange decision to use the ribbed tubing.

 

are the diffusers you are using from the same brand?

They are different brands. A "JARDLI Music Glass CO2 Diffuser" and "Clscea PMMA CO2 Diffuser"

The Jardli was the diffuser that worked for me for so long before.

 

So I got the problem fixed and there were multiple things going on so here's what was happening in case someone's reading this thread in the future...

First, both bubble counters I owned failed. The built-in check valves failed and didn't allow any air to pass through. Secondly, the tank of co2 I had was nearly empty. It's "Empty weight" was marked at 10.5lbs and when I weighed it, it was 11lbs. So I went to the LFS and replaced it with a full tank.

Thirdly, since I no longer use bubble counters or check valves, I placed my co2 tank on a counter above the co2 line going into the aquarium. This means the water won't back flow into the tank because gravity. After removing check valves and bubble counters, and getting a new co2 tank, my co2 diffusers are working properly.

 

Sounds like you have it figured out. Just as FYI, NilocG sells a reactor meant to work with the FX6.

I ultimately decided to try an atomizer/diffuser first and it's working fine for me so far, but I almost pulled the trigger on the NilocG reactor. It's the only one I could find at the time that is advertised to work with an FX6.

 

So I got the problem fixed and there were multiple things going on so here's what was happening in case someone's reading this thread in the future...

First, both bubble counters I owned failed. The built-in check valves failed and didn't allow any air to pass through. Secondly, the tank of co2 I had was nearly empty. It's "Empty weight" was marked at 10.5lbs and when I weighed it, it was 11lbs. So I went to the LFS and replaced it with a full tank.

Thirdly, since I no longer use bubble counters or check valves, I placed my co2 tank on a counter above the co2 line going into the aquarium. This means the water won't back flow into the tank because gravity. After removing check valves and bubble counters, and getting a new co2 tank, my co2 diffusers are working properly.

i dont use check value anymore for the same reason. kept failing. now i have 2 bubble counter. one as usual at the tank value outlet. the other is right at the top next to the tank before the diffuser pipe turns into the tank. and both counter display a different rate. i just look at the one near the tank and based on that cos its right next to tank and easy to read.

glad that you found your problems! always a relief.