Large Gas bubble in co2 diffusor

[Noddy65]

Hi all
Ive set up a DIY diffusor using a powerhead and garvel vac tube.
After its been running for a while (a few hours) a large gas bubble accumulates at the top of the tube.
It doesnt even go away after the CO2 has been turned off.
Is this undissolved CO2 or O2?
Whats the best way of getting rid of it? Is it worth getting rid of? I could drill a burp hole in the tube but wont this just release CO2?
Heres a pic of what I mean

Thanks
Mike

 

[MJProost]

As long as the bubble stays in the tube and the gas is not escaping the tube in bubble form it shouldn't be anything to worry about. In fact "burping it" would defeat part of the purpose of the diffuser. You want all the CO2 to break down in the water and not bubble to the top and escape into the atmosphere. I added some bio-balls and a piece of foam in the end of my DIY diffuser to break up the gas a little quicker and make sure it did not escape. But I still always had the bubble.

 

[Jay]

MJ
It is in all likelihood undissolved co2 gas and maybe a little o2 or other junk gas. The best way to make the reactor more efficient is to install a venturi loop from about 1" down your reactor tube up to your power-head inlet. The venturi will suck the co2 back into the water stream from the power head and back into the reactor agitation.

A little surface agitation of the tank water will also help to get more co2 dissolved. "A Little" is the key here.

 

[anonapersona]

More details please

I think the answer may depend on when the bubble appears. If the plants are bubbling away, then the bubble appears, then it may be O2 breaking out of solution as it goes through the pump. If it appears and grows before the plants are bubbling, then it may be excess CO2, you may need better mixing inside the reactor.

 

[Noddy65]

Well heres another development. The gas 'bubble' slowly increases in size during the day, then when the lights are out it reduces back to almost nothing by the time the lights come back on in the morning. The CO2 bubbles in at the same rate 24 hrs a day and the power head is always on.
I wonder why it disappears at night when there are no lights on but then reappears when the lights are turned on?

Mike

 

[Mooch28]

Well heres another development. The gas 'bubble' slowly increases in size during the day, then when the lights are out it reduces back to almost nothing by the time the lights come back on in the morning. The CO2 bubbles in at the same rate 24 hrs a day and the power head is always on.
I wonder why it disappears at night when there are no lights on but then reappears when the lights are turned on?

Mike

During the day, the small bubbles connect and become on big one. At night, they just disolve in the water leaving nothing.

It's nothing to worry about, as long as they stay in the siphon and don't escape.

Edit: Just realized you keep your C02 going all night........In that case........ :huh:

If all is healthy in the tank and doing well, don't worry!!

 

[Noddy65]

Everything is very healthy and growing well. Im just curious to know thats all.
I would have thought that as the plants are utilising CO2 during the day, the bubble would reduce or remain constant and then during the night when they arent using the CO2, the bubble would increase in size, but it appears that the opposite is happening?

Mike