# DIY co2 - turning it off at pm?



## growingthings (Oct 28, 2011)

how do you turn off a DIY co2 reactor at night? youtube states if u try it will go BOOM?


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## joekidwell (Aug 7, 2011)

growingthings said:


> how do you turn off a DIY co2 reactor at night? youtube states if u try it will go BOOM?


I would just loosen the cap so no co2 was going into the tank, it gets old after a while....another reason I went pressurized.


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## iKine (Aug 4, 2011)

I plumbed an air pump into my co2 line that comes on at night and dissipates the co2 into the room.


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## Daximus (Oct 19, 2011)

growingthings said:


> how do you turn off a DIY co2 reactor at night? youtube states if u try it will go BOOM?


If you physically shut off the flow (pinch or valve off the line), it will explode. The yeast/sugar reaction takes no time off and will pressurize the 2 liter until something gives. 

As the others stated, you could loosen the cap (thereby wasting the Co2), or you could add an air stone to the tank (thereby bleeding off the Co2). Either is acceptable.

I was worried about this as well when I started up mine, but I did some experimentation and found that neither was needed for my tank. Now, every tank is different...I don't want you gassing your fish on my advice. I'm in a 29 gallon tall, heavily planted, with 21 fish and a couple shrimp. I'm running one HOB that doesn't really churn the water too hard at the surface. No air stone. I leave my DIY Co2 running 24/7 and all my fish are perfectly healthy. 

I even ran two 2 liter setups like this for a few days and still, my fish were still fine. They didn't even hang around the surface. So you might want to just plan a late night and observe your tank one of these evenings and see what happens...if your fish all start hanging out at the top, gasping for air like little wet dogs...you have a problem. If not, set it and forget it. :icon_cool


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## kevmo911 (Sep 24, 2010)

I'd be willing to bet that if you're running anything less than one 2L bottle per 10g of tank, you don't have to worry about turning the CO2 off. You're simply not producing enough CO2 to harm anything, lights off or no.

DIY CO2 is definitely beneficial to plants. But it's not remotely close to being a substitute for pressurized CO2, even in very small tanks. No worries!


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## ddrfreak_tung (Sep 6, 2010)

Switched to pressurized co2 and it's pumping 3x the co2 compare to when I did DIY, I keep it on 24/7


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## growingthings (Oct 28, 2011)

thanks all. Didnt want to gas the fish or blow up the house. Cheers for your replies


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## somewhatshocked (Aug 8, 2011)

*kevmo911:* DIY can be and is a great substitute for smaller tanks. I've got three tanks that back it up. And pretty much exclusively use DIY on every 2.5gal-5.5gal tank I've got. Anything larger than 10gal, though, and it becomes a hassle, in my opinion and experience. 

*growingthings:* Definitely won't blow up your house. Most 2L bottles used today are rated for at least 90-100psi. At most, you'd just have a disgusting, smelly mess all over your room… and that is NOT fun. 

In a couple of my DIY setups, I plumb a cheap plastic knob/valve into my line that I can open up to gas off CO2 if it ever becomes too much. Never had to use it but it works well in testing.


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## JasonG75 (Mar 1, 2011)

What i did was remove the diffuser and place it in a cup of water overnight.

I used glass diffusers.


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## shane3fan (Nov 2, 2009)

Its going to take the path of least resistance. Just put a manual valve or electric solenoid on a line coming straight out of the bottle. Most of the CO2 will vent into the room with a setup like that.


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## SovXietday (Nov 1, 2011)

What I plan on doing is putting in a pressure relief valve using a manual boost controller (we use them on turbocharged vehicles). 

Simple ball and spring design. As pressure builds up, it pushes the ball and spring down a barrel until finally the pressure pushes the ball past a relief hole. They are fully adjustable from roughly 5-30psi normally, so on a low setting you will bleed off excess pressure but still retain pressure in the system and using a simple electronic solenoid set on a timer you've got a fully automated system out of the DIY. 

Speaking of which, if you want to know how much pressure your system is creating, you can put in a small manual air pressure gauge into the mix as well (< $20), once again super cheap on ebay and this will tell you when you're running out of CO2 and help dial in your system. 

At least, this is what I plan on doing in the coming months. I can build a diagram if anyone is wondering what in the hell i'm talking about.


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## kevmo911 (Sep 24, 2010)

That's a lot of rigging to do for a simple DIY system. If it makes you happy to build, go for it, but at some point you may find that the effort (and perhaps cash) you've invested in such a project may have been better spent on building a pressurized rig.

Still, it sounds fun


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## dundadundun (Apr 8, 2010)

if you use an internal powerhead powered reactor to diffuse your diy co2, you can simply put the powerhead on a timer to cut off at night. then the co2 just floats away as it blurps out until the power head kicks back on in the morning.


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## growingthings (Oct 28, 2011)

hmmmn....see I have a 30g tall tank which even though is moderately stocked has been limping along with just daily doses of Excell and a cheap n cheerful static plastic diffuser attached via an airline to a disposeable spray can of co2. Press it once a day and it disperses into tank over 8 hrs. Totally inefficient as theres no pressure and no bubbles but as cash was a priorty it was better than nothing. Now however some of my plants seem to be turning into skeletons, the fleshy parts of the leaves falling away to leave behind just the vein structure (mainly swords and Hygrophila stricta) I know the BNPs favour these and use them like swinging hammocks lol but I fear CO2 is now the issue esp now im using EI fertz. Im wondering if theres something in between DIY CO2 and pressurized?


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## damenblankenship (Nov 11, 2010)

a paintball set up is kind of in-between it's cheaper than a full on pressurized set up, and more effective than yeast. it all depends what you want to put into it. I've run diy on my tanks for years and had great success. I have never seen a reason to go to pressurized for myself. good luck!


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## Rich Conley (Jun 10, 2008)

somewhatshocked said:


> *growingthings:* Definitely won't blow up your house. Most 2L bottles used today are rated for at least 90-100psi. At most, you'd just have a disgusting, smelly mess all over your room… and that is NOT fun.


 
Having played around a bunch with fermenting beer under pressure, yeast will shut down well before they get to 90 PSI. 

On the other hand, opening a coke bottle at 50PSI probably would make a mess anyways.


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## galabar (Oct 19, 2011)

I use the internal powerhead reactor approach for my DIY CO2. I just plug the powerhead into the same timer as the lights.

I'm guessing that this gives me a more stable pH -- that the increase in CO2 and reduction in O2 production by plants at night will somewhat compensate for the reduction of injected CO2, leading to a more stable pH. However, it might not compensate for the lose of a bunch of CO2 in the water column (I really need to test this).

Have others seen better (smaller) pH swings when shutting off CO2 (as opposed to leaving it on). For me, the wasted CO2 cost is minimal. I'm much more interested in the health of my fish (I don't think the plants care all that much about the pH swing).


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## Aquariumanexiety (Jun 8, 2013)

I am almost positivetThere is no way the co2 2L bottle would expload..... Soda bottles can usually hold 115 psi befor exploding.( tested by me when making air cannons). Yeast is not capable of making this high of pressure. There just is not enough energy stored in it. My dad also accidentally pinched my line on my set up by dropping stuff on it. It was pinched for two full days and it barely stretched the bottle. Ps. Before they expload they stretch ALOT kinda like a balloon so if you glance at the bottle and it doesn't look extremely deformed its not gunna blow. The seal connectig th hoses to the bottle will definitely go first. Even the hose might burst before the bottle. Lol


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## aaronbrown (Apr 13, 2010)

why not put a y in the air lines and put in a couple valves and shut off the one going to the tank and open the other one a lil to off gas some pressure so as bottle dont explode


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## Hilde (May 19, 2008)

somewhatshocked said:


> In a couple of my DIY setups, I plumb a cheap plastic knob/valve into my line that I can open up to gas off CO2 if it ever becomes too much. Never had to use it but it works well in testing.


Got a pic of it? Where did you get the knob/valve?


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## Hilde (May 19, 2008)

JasonG75 said:


> What i did was remove the diffuser and place it in a cup of water overnight.
> 
> I used glass diffusers.


I like that idea. 

You have DIY Co2 with just the yeast mixture in bottles hooked up to a glass diffuser? Read that they don't always work with DIY Co2.


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## somewhatshocked (Aug 8, 2011)

All right for bringing an old thread back to life, folks.

It's absolutely not necessary to use a valve.

But you can get them at any aquarium retailer or even a plumbing supply center. Airline gang valves work and so do flow restrictors that are connected with an airline T.



Hilde said:


> Got a pic of it? Where did you get the knob/valve?


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## Hilde (May 19, 2008)

growingthings said:


> Im wondering if theres something in between DIY CO2 and pressurized?


On Ebay I have seen DIY Co2 kits for sell. More info here


Hoppy said,"It would be very difficult to get enough CO2 from one 2L DIY bottle to do the slightest harm to the fish. Wit a 45 gallon tank I used 2 -2L bottles, and never got more than about 20 ppm of CO2" Thus will experiment with this theory.


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## TheDrake (Jul 18, 2012)

:thumbsup: +1 on running the CO2 into a powerhead on the same timer as the lights. 

I disagree that DIY is only for small tanks; I do it on ~200 gallons. :biggrin:

I also disagree about the explosions. I've done it with DIY beer and root beer (albeit in glass bottles). Still have the marks on my ceiling to prove it :eek5:


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