# diy co2



## aquaman73177 (May 20, 2008)

I'm trying something that might be risky...I've got my homemade co2 (yeast/sugar/baking soda) from 2 liter bottle tapped directly into hob filter intake. Using airline tubing. It's only been a few hours and I can already hear/see bubbles. One bubble every 30-45 seconds. 

Specs:
5 gal hex
no carbon in hob filter (took out, replaced w/ polyester batting)
15 watt compact flourescent (6700k daylight)
vermiculite/gravel substrate
dwarf sag, water sprite, java fern

I hesitated to "put it all out there" (don't want to look foolish). Just wondering...am I going to screw something up? Comments welcome. Thanks.


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## customdrumfinishes (Apr 4, 2008)

the c02 should be fine. the bubbles shouldbe pick up the pace by now. im trying a 2.5 cups sugar, 2 cups water and about 1/2 tsp of yeast mixture. has been bubbling for 3 days strait every sec so far. about 15 bubbles a sec


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## starsunmoon (Apr 5, 2008)

I found out that the baking soda helps the yeast not eat the sugar so fast !! so yea I am going to add a tsp to all my bottles today !! hey its worth a shot!!!

sounds like your doing fine, the co2 into the hob filter sounds interesting , can you post pics??? I would LOVE to see this in action, maybye it would work for some of my tanks >>>>>


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## aquaman73177 (May 20, 2008)

i would love to post pics...for a young guy i'm pretty techno illiterate, so it may take me a while to figure out how to do it. in the meantime...I've just got the airline tubing coming from the 2 litter bottle, looped down and back up into the tank. i use a small rubber band to keep the tubing close to the filter intake. I had to cut a section out of the filter guard to get it to fit in there. When a bubble comes out, the impeller sucks it right up, breaks the bubble into smaller ones. My understanding is that the co2 can then get trapped in the filter media and diffuse. I'm seeing tons of tiny bubles coming out of the filter spout...i've got some cabomba close to it, and those tiny bubbles seem to be "sticking" to the underside of the leaves. i'm new at this, but I think that's good. 

customdrumfinishes-I'm now getting about 1 bubble/second. 

Something else I discovered...since I don't have any type of check or regulator valve, I was worried about co2 pumping into the tank all night and creating a surplus (maybe a problem, maybe not). To solve this, I've been loosening the bottle cap until the bubbles stop being sucked into the intake. The next morning, i tighten the lid back down, and presto! bubbles start back up within a minute. 

Hope this helps someone. everybody's been helpful to me.


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## octopus44 (Apr 23, 2007)

When I had DIY CO2 I had the best luck when I ran the bubbles through a pump, so your method should work fine. 

I wouldn't worry about bubbles continuing through the night. At such a low bubble rate I doubt you will have too much CO2 buildup. 



aquaman73177 said:


> Something else I discovered...since I don't have any type of check or regulator valve...


If you dont have a check valve I would strongly consider getting one. It will prevent water from siphoning into the DIY bottles which can cause your yeast solution to get into your tank which can be disastrous. You can pick them up cheap at petco.


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## customdrumfinishes (Apr 4, 2008)

you need check vavle for sure! dont want c02 mush in the tank!!!!
i have my c02's on power heads. i see people drilling a hole in the hob filter to put the c02 in it so it blows the bubbles around some. line blow halfway across the tank so its getting around fine.


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## fshfanatic (Apr 20, 2006)

starsunmoon said:


> I found out that the baking soda helps the yeast not eat the sugar so fast !! so yea I am going to add a tsp to all my bottles today !! hey its worth a shot!!!


That is not true. When the bacteria feed on the sugar it turns the solution acidic, the baking soda helps to prevent this and prolongs the reaction time. As acidic water kills bacteria.


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## fshfanatic (Apr 20, 2006)

customdrumfinishes said:


> you need check vavle for sure! dont want c02 mush in the tank!!!!


A check valve will not stop this unless installed backwards, if you installed it this way CO2 would not be able to enter the tank either.


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## customdrumfinishes (Apr 4, 2008)

i guess you dont need a check valve then lol..

octopus44 wrote..
If you dont have a check valve I would strongly consider getting one. It will prevent water from siphoning into the DIY bottles which can cause your yeast solution to get into your tank which can be disastrous. You can pick them up cheap at petco.

he must be wrong to.


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## fshfanatic (Apr 20, 2006)

It stops water entering your bottle from the aquarium it free flows the other direction.


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## customdrumfinishes (Apr 4, 2008)

but the co2 mush can still get in the tank, i guess theres no way to prevent it?


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## fshfanatic (Apr 20, 2006)

customdrumfinishes said:


> but the co2 mush can still get in the tank, i guess theres no way to prevent it?


Use a gas separater/bubble counter. Problem solved


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## aquaman73177 (May 20, 2008)

other than the bottle tipping over (possible), I'm not sure how the mixture could get into the tank. I've had the system running for 3 days now, and the pressure from the gas keeps water out of the tubing.


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## classclown (May 11, 2008)

I don't have any experience with co2 at all, but in reading different web pages and forums, the only times people talk about the mixture getting into their tank is when they over fill the bottles. Apparently the mixture is being deprived of adequate space to create the gas so the whole mix then travels up the tube.

I think if a mix is too rich this can happen also. 

I've also noticed that some people use a smaller empty pop bottle between the mix and the tank like a water trap in an air line to catch some sort of scum or some such.


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## classclown (May 11, 2008)

aquaman73177 said:


> ... I've had the system running for 3 days now, and the pressure from the gas keeps water out of the tubing.


I would think that as the co2 production diminishes you will eventually lose the pressure and then the water pressure in the tank will cause water to siphon back down the tube into the bottle.

However, I have no idea what the ramifications of that would be exactly.


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## Zer (May 23, 2007)

classclown said:


> I would think that as the co2 production diminishes you will eventually lose the pressure and then the water pressure in the tank will cause water to siphon back down the tube into the bottle.
> 
> However, I have no idea what the ramifications of that would be exactly.


This, certain situations could cause negative pressure in the bottle and then bam, tank water floods it. After that, the yeast sugar process can consume all of the oxygen in the tank and do other things to really throw it off. 

Sorry i can't give a better description, but I am a bit rusty. You really do want to go spend 3 dollars on a check valve though (configured to allow flow from the bottle to the tank, but not from the tank to the bottle).


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## aquaman73177 (May 20, 2008)

The water that siphons back into the bottle (this happens sometimes) simply drains down into the mixture. Since the end of my air tube is up near the cap, there is no way for the water in the tube to mix with the mixture and then re-enter the tank. The CO2 gas pushes the excess water back out of the airtube, and the the gas starts bubbling like nothing ever happened. The only way I could see the two liquids mixing is if the mixture level inexplicably rose to the level of the air tube. Again, I'm a newbie, and am only theorizing. Strange things happen when laymen start experiment'n with science!


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## aquaman73177 (May 20, 2008)

just to be safe, i am getting a check valve. :icon_idea


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## reddragon1977 (May 30, 2007)

I had my DIY hooked up and went away for vacation with no check valve. When i got back i could see that the flow had changed back into the bottle as there was water throughout the line straight back into the bottle and no C02 comming out. The whole unit was dead...nothing moving. And NOTHING HAPPENED! I tore it our and checked my levels and everything was the same so i blew out the line remixed my sugar/yeast/baking soda and rehooked it up. Not sure how it happened or how long it was like that(min right then-max 2 weeks) but nothing was different. but thats just my experience and im not telling you not to get a checkvalve im just not sure its needed.


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## aquaman73177 (May 20, 2008)

reddragon,

do you run air tubing into intake of hob filter? powerhead? what's your diffusion method? just curious.


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## reddragon1977 (May 30, 2007)

i purchased a kit from hagen and was paying for the packs until i learned it was sugar and baking soda. I still use the bubble ladder that came with it. Its amazing how when you say sodium bicarbonate you can charge another $5 overbaking soda  tisk, tisk, hagen 
I mix up a batch and close it up, when the bubbles space apart to long on the ladder i unhook dump and refill. The setup last about every 3 to 4 weeks between changes. I think you can see it in my old pic in my profile in the back left....which reminds me i need to update that pic


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## aquaman73177 (May 20, 2008)

nice tank! my sag sucks compared to that!:icon_sad:


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## reddragon1977 (May 30, 2007)

thanks, It did nothing and i mean nothing for 2 months. I then split it up and have to mow it on a byweekly basis. This stuff is not so "dwarf" and will easily reach the top of the tank if i let it. Each one shoots out another plant every 3 weeks or so. I wait until they are about 3 inches tall and then i cut the umbilical cord  Then you will have 2 plants shooting off in the next few weeks. and so on and so on. That sag started with one bunch. that stuff if more like a weed than an aquatic plant. (its long stringy duckweed)roud:


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## reddragon1977 (May 30, 2007)

sorry got way off topic there. with the diy check to see if you can buy a bubble ladder on ebay/craigs list or something. Im not sure but hagen may even sell replacement parts. It not really a difuser but it works okay for me and it super easy to hook up (just hide it better then i did behind some taller plants)


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## kittytango (May 7, 2008)

If you keep the yeast bottle above the tank then nothing can siphon into it or back out of it. I keep mine on top and the heat from the lights seems to make it produce bubbles faster. Do you guys keep yours hooked up all night? I take the cap off at night so no Co2 enters the tank.


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## aquaman73177 (May 20, 2008)

i was loosening the lid, but then I started leaving it on all night...i'd heard you can cause ph swings by having it on, then off. but don't the plants emit co2 at night anyway? i get basically 1 bubble/second. i don't know if that's enough to even worry about...


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## reddragon1977 (May 30, 2007)

Im really just set it up and forget about it for a couple of weeks. I also dose Excel so there should be lots of carbon. If you guys can get it then I would start using it right away. IMO its the best thing you can do for your tanks. I havent tested the water to see how much it goes down but it has to be minimal as the shrimp and neons are not affected at all


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## mavisky (Jun 18, 2008)

For reference my newest mixture is:

5 cups water - 80-90 degrees or so
2 cups sugar
1/2tsp yeast

2 2liters filled with this per diffuser, 2 diffusers per tank - total of 4 2 liters. 

Bubbles like mad and has so far dropped my ph from 7.4 to about 6.6. We'll see how long this mixture lasts. I'm predicting it'll die off pretty quickly at about the 1 week mark.


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