Bubble counter liquid vanishes

Background. I am just starting to explore pressurized CO2 for my planted tank. I have tried it briefly on a nano tank and am now testing an installation on a 90g tank. This is a first post.

 


The Issue. I had the bubble counter installed for a few weeks on my 90g tank and it was working fine, although using it with an in-tank diffuser seemed not particularly efficient in terms of diffusing sufficient CO2 to make a difference. When I connected up an inline CO2 diffuser to my Fluval 406 output, it seemed to work well. However I have noticed that for two successive nights, the water in the bubble counter disappears overnight (when the solenoid switch and CO2 flow is off).

 


Troubleshooting. I haven't detected any water outside the bubble counter or hosing. I am of course concerned about water leaking down into the solenoid etc. (I haven't had an additional checkvalve appropriately installed between the solenoid and bubble counter). I expect bubble counter water to evaporate slowly with the CO2 over days or weeks and have seen this, but am mystified at its disappearance overnight with the CO2 flow off. Perhaps it is leaking back down through the bubble counter checkvalve and into the solenoid but how does it disappear? I find no traces of water or leaking although I haven't disassembled the system as yet.





Is there something basic I don't get or am overlooking?


Thank you for any insights!


Photo 1: The inline assembly.


Photo 2: (CO2 hose is disconnected in this photo). I had installed a checkvalve above the bubble counter, but when I tried to remove it, it broke. (Maybe because it is a regular plastic aeration check valve and not designed to be used with CO2--or maybe just cheap). Regardless of what my water disappearance issue is, I recognize I need to find some appropriate check valves (brass?) to go above and below my bubble counter for security.

 

No apparent leaking. I have since filled it up and tried again--now without a problem so I feel kinda stupid. There is of course slow evaporation of the water in the bubble counter.


​I tried adding a cheap plastic check valve (described as for CO2 or aeration), unfortunately the connection with the tubing was not sealing properly and I could hear the CO2 leaking so I removed it. I understand there are a couple of different airline hose dimensions available, so maybe that's the issue. In the meantime I am looking for a better reliable check valve solution that hopefully doesn't cost the earth.