DIY CO2 question about check valve

[swanandmokashi]

I am an idiot I did the CO2 system without a check valve and the water came back from the tank to the bottles.

Anyhow, question is : which check valve do you guys use? plastic ones (the ones available at pet stores) or metallic? (if metallic where can I buy metallic ones) -- also where do I put the valves --BEFORE the T joint or AFTER it?

-- so basically one valve per bottle or 1 per 2 bottles?[/img]

[Purrbox]

When I was using DIY CO2, I used the plastic ones and never had any problems with them. You do have to replace them about once a year since the CO2 will slowly break down the plastic. You can put them before or after the T connector, it's mostly personal preference. I preferred putting them before the T so that the rest of the system would stay pressurized when changing out one of the bottles.

[Sicklid]

I preferred putting them before the T so that the rest of the system would stay pressurized when changing out one of the bottles.

So, besides keeping water from flowing backwards into the system, when you disconnect one bottle the check valve keeps the rest of the system from losing pressure? I could smack myself for not seeing the obvious! I meant to ask you about that when I saw your system, Purrbox.

[tropicalfish]

I think using two individual check valves is also better because in the event that the check valve gets stopped up, you will only have one bottle adding pressure on it, instead of two...

[leoslizards]

This might be a really dumb or n00bish question but here it goes.. <_<
>_>

Which way are the check valve suppose to go? I never really known because I always bought them in bulk so I never got to see the instructions.

I'm also a little confused. How does a check valve help a bottle keep it's pressure?
Maybe I'm thinking of something else.

Check Valve


Gang Valve


I could understand how the gang valve can be closed and let the bottle keep it's pressure but not the check valve.

I did my 1st DIY Co2 system today and I added two check valves and a gang valve to it. The gangV was put on the edge of the back of the tank with a checkV right underneath it so that water won't siphon up the tube. The 2nd check valve was put on the tube that went from the back of the gangV to the bubble counter cause I had the impression that the water from the bubble counter and/or the sugar/yeast mixture could siphon up the tube and contaminate my tank. I could be wrong.

After about 5 to 6 hours I notice that no gas was going into my tank. Then I realized that the checkV only allows air to enter one side and out the other. Not the other way around. I had placed the checkV at the top with the "V" rubber center thing facing down as well as the other one near the bubble counter. It's kind of hard to explain so I drew a pic. Sorry my digital cam batteries ran out and I lost my charger.



As you can see, the lower checkV wouldn't allow the gas to go into the tank so I turned it around and hopefully I'll be able to get Co2 into my tank tomorrow. I also haven't seen bubbles come out of the counter so I was thinking of removing it and just connect the tubes together.

[Purrbox]

In a more standard setup where the two generator bottles are connected by a T and go to the same CO2 diffuser, if you unhook one bottle the entire system will loose pressure. If you place a check valve between the T and the diffuser, when you change a bottle both bottles and the line upto the check valve will loose pressure but the line between the check valve and the diffuser will stay pressurized. Now if you use two check valves one between each bottle and the T, then only the bottle being changed and the line to its check valve will loose pressure, but the other bottle and the line leading to the diffuser will stay pressurized.

Hope that makes more sense.

[Sicklid]

The very reason a check valve exists is to prevent backflow, either fluid or gas/air... SO when you have it setup the way Purrbox describes w/ one check valve on each bottle before the "T" and you remove a bottle, the pressure from the system should shut the open valve...

[tropicalfish]

the "arrow" thing in the checkvalve is the direction of airflow. If you need to, you can do a simple blow test.

[leoslizards]

Originally Posted by tropicalfish

the "arrow" thing in the checkvalve is the direction of airflow. If you need to, you can do a simple blow test.

Yeah I did that. I connected them to an airpump and that's how I realized that they only allow airflow in one direction.

Today I changed my DIY Co2 system a bit. I removed one of the check valves and the bubble counter and I added an air control valve between each bottle and T valve. Everything seems to work alot better and I'm actually getting Co2 in my tank now!

Today I also made a DIY powerhead type filter using a water pump, a gravel cleaner, and floss. It came out awesome but it's way to powerful. The flow moved my gravel and pulled out some plants.

[/img]

[swanandmokashi]

actually I have a spare powerhead -- how can I use it with my CO2 system?