# DIY Co2 - switching off at night



## sevenleaf (4 Jun 2008)

I am currently running a primative DIY CO2 setup consisting of a 1.5l fizzy drinks bottle with a bulkhead connector to attach the length of co2 tubing - that leads to glass ceramic diffuser in the tank.

This setup is working very well, although if anything, slightly too well. My 4dkh drop checker is yellow in the mornings, and slightly lime green at nights. Other than simply unscrewing the lid of the bottle at night, what can I do to regulate the co2 to the tank?

I considered putting a flow restrictor in the line on that came with my air pump, but I don't want my rig to expode. I then thought about having a splitter; at night I could divert the co2 to just flow into the cabinet [a waste, I know, but I'm not too bothered] and then diverting it back into the tank by day.

What solutions have others successfully employed?


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## LondonDragon (4 Jun 2008)

Run an air stone for a few hours when the lights are out, the surface agitation will get rid of the CO2.


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## beeky (4 Jun 2008)

Yeah, you could put an airpump on a timer to come on overnight and then turn it off about an hour before lights on.


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## beeky (4 Jun 2008)

Thinking about it from a different angle, how about changing your mixture. If you put less yeast in I believe this would reduce the output but would last longer. Or is that sugar? Not sure!

Of course, a yellow drop checker doesn't necessarily mean there's excess CO2 all over the tank, it could be a concentration of it. Try moving your drop checker and see if it changes.


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## Ray (4 Jun 2008)

Never tried this but I guess you could add a T piece with a solanoid on one fork, diffusor on the other.  Set the solanoid to open at night, allowing the CO2 to vent rather than going through the diffusor.


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## sevenleaf (4 Jun 2008)

LondonDragon said:
			
		

> Run an air stone for a few hours when the lights are out, the surface agitation will get rid of the CO2.



Thanks for all of the fast replies guys - I think I'll try this one first as I have all of the required bits and pieces lying around anyway.


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## Wolfenrook (4 Jun 2008)

I used to mount a small water pump at the surface set to come on at night.  This way the increased surface agitation drove the excess off at night.  Worked fine.

Ade


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## LondonDragon (4 Jun 2008)

sevenleaf said:
			
		

> Thanks for all of the fast replies guys - I think I'll try this one first as I have all of the required bits and pieces lying around anyway.


I do this in my tank even though I use pressurised system with selonoid valve, the fish deserve a break too


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## aaronnorth (4 Jun 2008)

I took this statement of TFF from duzzy:



> the tap is just a normal aquarium tap it goes like this: yeast factory valve t with condom tap you turn the tap off and overnight the condom blows up in when you turn the lights on turn and the co2 on over the course of the day the condom slowly goes down I tried a balloon but the rubber was to tough i stretched the condom a few times and worked, still tweaking it as soon as i get it finalized will post on the subject. As for thinking of it I was watching my little niece trying to blow a balloon up she would get so far and when she took a breath it went down and bing the light bulb went off and ooh


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## sevenleaf (5 Jun 2008)

aaronnorth said:
			
		

> I took this statement of TFF from duzzy:
> 
> 
> 
> > the tap is just a normal aquarium tap it goes like this: yeast factory valve t with condom tap you turn the tap off and overnight the condom blows up in when you turn the lights on turn and the co2 on over the course of the day the condom slowly goes down I tried a balloon but the rubber was to tough i stretched the condom a few times and worked, still tweaking it as soon as i get it finalized will post on the subject. As for thinking of it I was watching my little niece trying to blow a balloon up she would get so far and when she took a breath it went down and bing the light bulb went off and ooh



Nice idea, I like it! I'm very new to the CO2 thing so still trying different things, but if it meant that I could make a mix with less yeast, so the whole mix lasted a little longer then that's a winner as far as I am concerned!

I was looking through my box of tricks last night and found a non return valve which I stuck on the CO2 line. It appears to have increased the resistance before the diffuser and therefore reduced the flow - but I don't know if this will be a long term solution - I guess the CO2 will still be produced at the same rate and therefore the pressure will just rise until it was as before.

Airstone it is though!


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