# Other Aquarium Forums > Equipment and Accessories > DIY Projects >  DIY coke bottle CO2 and glass diffuser

## hebi

hi all,

i know this has been mentioned quite a few times and i notice that some managed to force CO2 out using their DIY CO2 while others cant and say the bottle may explode? :Shocked: 
i decided to try it out myself and bought a cheap $5 taiwan brand glass diffuser from polyart. after nearly 2 hours, no bubbles is coming out from the ceramic plate yet. there are a few things i want to clarify:

1) is the glass diffuser supposed to be filled with water in it? i thought maybe extra pressure needed to push the water out too if got water.

2) for those who did succeed in using glass diffuser with your DIY CO2, can tell me what bottle/container you are using and how long it took to build up enough pressure?

i dont know whats the max my 1L coke bottle can tahan. is it when i try to squeeze the bottle but cant squeeze then is maximum already?

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## Shadow

I'm using flipper and it took 24 hours to get fist bubble comming out and it is about 1 bubble every 2 second. With ceramic diffuser it may take longger.

It not suppose to be fill with water.

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## bossteck

Hi, 

1) No. As air escapes from the diffuser, water will enter the diffuser, you don't have to, and it is very difficult to fill it up beforehand. 

2) Can't comment on this as I have never tried it before. 

My 2 cents is, you will probably be better off exploring other methods of diffusing your diy co2, can consider diy'ing a co2 diffusion bell?

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## PeterGwee

Use tom barr's DIY Internal Venturi Reactor. Do a search in the forum and you should find it.

Regards,
Peter Gwee

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## hebi

> Hi, 
> 
> 1) No. As air escapes from the diffuser, water will enter the diffuser, you don't have to, and it is very difficult to fill it up beforehand. 
> 
> 2) Can't comment on this as I have never tried it before. 
> 
> My 2 cents is, you will probably be better off exploring other methods of diffusing your diy co2, can consider diy'ing a co2 diffusion bell?


i have tried that before. but the diffusion rate is slowwwwww. what do you guys think about using a limewood diffuser( requires less pressure but also produce small bubbles) with a bell method? because my tank is only 1ft so will like to keep things neat.

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## Shadow

Problem with diffuser is algae can grow on the surface and block it. Pressure will keep increasing and your bottle burst.

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## hebi

Good news!! :Grin:  i change my glass diffuser for a limewood diffuser and within 1min, tiny bubbles are coming out. its really small , almost like those from using ada diffuser. hope my spiky moss and moss ball can grow better after this. thanks all for your advices.

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## bossteck

Great to know that. Since you're using DIY co2, which I presume logically will be feeding your tank with co2 24/7, having too effective a diffusion method may not be a good thing after all. 

Cheers!

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## Aeon

Some diffusors need pressure to operate. Your DIY bottle probably wasn't pressurized enough to push the gas through the tiny pores of the ceramic plate.

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## hebi

seems like good things dont last long. :Sad: i woke up today and discover that no bubbles are coming out from the limewood :Exasperated:  i test if its working by softly squeezing the bottle and bubbles came out. reason could be the slimy stuff that is formed wif DIY CO2 that clog up the limewood or lack of pressure. shall wait and see.

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## tawauboy

what's the quantities of yeast and sugar did you use?
did you check if there are any leakages?

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## peter2883

I think you are better of with a CO2 reactor... You can try to find the external ones so that it does not clog up your tank...

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## Shadow

For DIY, in my opinion, fliper still the best. Even with externa reactor, depending on your pump flow rate, you have water pressure from your pump that agains your CO2 pressure.

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## hebi

i use 2 cups of sugar( cup around 10cm height and radius 2cm), 1/2 teaspoon yeast and 1 teaspoon baking soda in a 1L coke bottle. the yeast is still working, i can still it producing lots of bubbles. i have checked there is no leak. but i notice that bubbles are having a harder time just coming out from the tube if i place the opening of the tube facing the bottom. pressure i guess? think i will reuse the bell method till i get myself a pressurized CO2 tank at the end of the year after my A's  :Jump for joy:

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## juggler

> seems like good things dont last long.i woke up today and discover that no bubbles are coming out from the limewood i test if its working by softly squeezing the bottle and bubbles came out. reason could be the slimy stuff that is formed wif DIY CO2 that clog up the limewood or lack of pressure. shall wait and see.


Did you use a 2nd bottle which serves as a bubble counter and also to dissolve some stuff which causes the slime buildup?
See this setup http://www.thekrib.com/Plants/CO2/co2-faiz.html

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## hebi

nope i didnt use that. i thought the purpose of that is to prevent tank water to get into the yeast solution and vice versa? anyway, whats the slimy thing? also, i saw a video on youtube, title is something 100&#37; diffusion, looks nice and seems effective.

O/T: anyone know where i can find aquascaping books like 'the style of ADA' and aquajournal? kinokuniya?

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## Shadow

NA sell those book

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## tawauboy

recipe looks ok.
having a bubble counter helps to reduce slime build up.
remove the limewood diffuser and see if you have co2 coming out of the tube.
try replacing the limewood diffuser or search for a plastic airstone.

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## hebi

ya there is bubble coming out but much slower compared to a week before though. not consistent as in like sometime every 12 sec 3 bubbles. the thing with plastic airstone is that the bubbles are much larger, but still better that just the big bubbles. anyway, can someone tell me how does the slime form? does it mean if i use a bubble counter( is it the seperation bottle or really those kind like a glass tube ?), the slime will form at the bubble counter instead of the outlet?

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## blackghost

hi, before i got my co2 tank, i too used diy.. this is my experience..

i installed a 1 way valve.. so that only the gas can pass through.. without the water being sucked back.. 

i used a flipper as my diffuser. almost got myself the glass ceramic diffuser, but the LFS uncle advised not to as DIY co2 not enough pressure..so get a flipper instead.

and.. i ensure there is no leakages by spraying soap water on the connection points, if the soap water bubbles means there is a leakage..

also, i get bubbles after minimum 2 hrs.. and last for about 1 - 2 weeks.. 

cheers

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## hebi

hi all, another question to all DIY CO2 user.my DIY Co2 is still producing CO2 as can be seen from the solution. however no bubble is coming out from the tube( i just use a bell to collect CO2)i dont know is it not enough pressure to even push the CO2 out or is that a leak somewhere, only possible place could be at the cap. for me, i drill a whole into the cap, then screw in the outlet(valve like thing bought at C32 :Cool:  those metal kind then it seems pretty tight. today i went near it and i could smell alcohol, so should i just seal the metal screw outlet with the cap? or is it normal to be able to smell alcohol for a DIY CO2?

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## blackghost

you shouldnt be able to smell the alcohol or the yeast solution..

use silicon or for my case, blu tack to provide the seal when the tube goes through the hole in the bottle cap so that air cannot escape through..

once you done that, use the soap water method to check for leaks.

another thing, if u smell alcohol, it means that the sugar water is also done fermenting.. so not much co2 will be emitted.

my 2 cents  :Roll Eyes:

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## tawauboy

> .......... those metal kind then it seems pretty tight. today i went near it and i could smell alcohol, so should i just seal the metal screw outlet with the cap? ............


chances of a leak is pretty high. you'll need to seal this joint well. use glue or sealant.
there shouldn't be any alcohol smell if you do not open the co2 bottle. a sign that there is a leak.

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## Shadow

you can use epoxy glue, but probably not woth to buy new epoxy just for that  :Smile:

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## hebi

> you can use epoxy glue, but probably not woth to buy new epoxy just for that


whats that? is it the glue gun kind of thing? i have a glue gun but think rather troublesome to use it. time to make another bottle, hopefully will generate enough pressure to push through limewood at least :Opps:  the algae on the glass is really an eyesore.
edit: ok i know whats that glue, have that too at home haha, those kind need to mix 2 glue together.but is it worth the effort? if really can seal very tight compared to superglue, i dont mind using it. the instruction on the tube made it seems as if its dangerous to use that.

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## Shadow

Yup that is the one, need to mix first. If you have it at home, why don't you use it? it is quite simple. The material used in softdrink bottle is somewhat un glueable. I can't remember the material name and I found only epoxy work with it. You also need to scratch the surface to get better grip.

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## hebi

what do you mean by scratch? so do i glue the screw part of metal thing in or apply the glue at the tiny gap ?

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## Shadow

You are using screw? Can you just tighten it up?

I was thinking that you just drill hole in the bottle cap and slot in the air hose connector.

You can scratch the surface of the bottle using pen knife

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## hebi

ya i using those screw kind. but although can tighten, still got slight leak at the hole there coz when you screw in, the cap will light dent in slightly. do you think epoxy glue can glue plastic and metal together?

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## blackghost

cheapest solution is to use blu tack.. the one used as stationery.. 

just apply and makes sure there is no holes..

or you can get a tube of silicon, 1 small tube about 4 dollars.. can get from hardware shop or LFS.

cheers

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## bossteck

If you're using a screw-type air tube connector, another cheap solution I can think of is to use those white teflon tape (commonly referred to as white tape or plumbing tape), wrap a few round around your tube connector and screw it back into the bottle cap, should be able to achieve a better seal.

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## hebi

ok. think blu-tac easier to use and cover. what about plastacine? also can right?

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## Shadow

Agreed, if it screw type, just use blu-tac to seal the leak.

By the way where did you get the screw type air tube connector?

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## hebi

C328, all the airstones and equipments there. got think thats the only place got sell this kind in the west side.

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## hebi

sorry asking newbish questions, but yesterday i made another bottle and connect the 2 bottle to a connector, and all my connectors have a 'switch' to airflow. so i thought it will need some time to build up pressure in both bottle for it to push the CO2 into the water. strangely, for my brand new bottle, its already producing CO2 and i have test for signs of leaks but the water level in the tube connected to the main connector is not decreasing. so i decided to 'switch off' the side from the new bottle and just use the old CO2 bottle, which is still producing CO2. now, it can push CO2 out of the bottle, but after maybe a few bubbles, the water level start to rise till halfway then stop, lower than when using the 2 bottles together. why is this so? really strange. :Huh?:

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