# Best DIY CO2 Diffuser & Recipe



## gratts (26 Feb 2009)

Hey all.
I'm currently just dosing easycarbo, but have all the equipment still lying around for DIY CO2, so thought I may as well set it up again to run alongside the easycarbo.
So two things
1) What have people found is the best recipe?I have some fancy champagne yeast which is supposed to keep going for longer   Tank is 100L - I figure I'd run 2x2L?
2) What is the best diffuser to use? I used a limewood diffuser on my 20L and wasn't really impressed. It seemed to go mouldy/slimy very quickly. I don't mind buying something as long as it's quite effective!

Thanks


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## a1Matt (26 Feb 2009)

2 x 2l worked for me on a 160l.  Staggered them to run out at different times of course.  Used ordinary bread making yeast they had in Sainsburys. 

Barr internal reactor with venturi loop is a very efficient reactor. built mine with a Â£3 pump off ebay and an old gravel cleaner. I turned the pump on the reactor off at night, so I didn't get any CO2 build up in the tank.
http://www.barrreport.com/articles/41-d ... users.html

Never had a drop checker at the time so couldn't tell you the concentrations I reached, but the plants did well.  Only stopped cos I got fed up making the mixtures and keeping an eye on it.


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## gratts (26 Feb 2009)

Excellent, thanks for the link.
I have a spare tube from a broken gravel cleaner and an old Juwel powerhead, so that could be perfect   
I know what you mean about the hassle. I just have no income right now so as much as I wish I could, I can't justify going pressurised


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## a1Matt (26 Feb 2009)

gratts said:
			
		

> Excellent, thanks for the link.
> I have a spare tube from a broken gravel cleaner and an old Juwel powerhead, so that could be perfect
> I know what you mean about the hassle. I just have no income right now so as much as I wish I could, I can't justify going pressurised



Your welcome.  

The pump I used was really low flow.  If the bubbles get pushed out of the bototm of the reactor then you need a longer tube or a lower power pump.  If on the other hand you get a gas buildup and the venturi loop does not remove it, then you need a higher specced pump.  Enjoy making yours 

I think I kept a notebook which had the amount of sugar\yeast I used, I'll see if I can dig it up when I get home tonight.


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## gratts (26 Feb 2009)

Right, I'm officially flummoxed!
Can't really make head or tail of the Tom Barr reactor.
Are there any other guides out there with step by step pictures? (And maybe big text with bright colours..  )

What's the function of the venturi loop thing?

Is it basically a better version of something like this?





Seem to have thrown out my plastic cylinder, so will have to find some more


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## gratts (28 Feb 2009)

Very small bump..


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## Ed Seeley (28 Feb 2009)

Basically it's the same thing, but that reactor would need mounting upside down IMO with the CO2 in at the bottom or have the CO2 injected into the flow before the reactor.  The injection point then could form a venturi loop.  This is basically where you have a fitting that is posistioned where any gas might build up in a reactor and that fitting takes the gas from there and re-injects it lower down using the venturi principle to suck the gas out.  If you were using a powerhead you can use the venturi fitting on it to do this.


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## a1Matt (3 Mar 2009)

As Ed says CO2 in at the bottom of the tube.  Power head pushes water down and out the bottom of a tube.  The CO2 bubble rises against the flow, gets stuck in the middle and pushed about\broken up.  That way the water coming out the bottom is CO2 enriched.

If the venturi design confuses you then you can simply miss it out   

I just had an opened bottomed tube, no outlet nozzle thingy.  Just a big hole for the water to come out of.  Will see if I can dig up a picture of mine (pm me again if I forget!).

As it is in the water it does not have to be watertight in anyway, mine was a pretty crude affair.  Did a great job though   

I PM'ed you my CO2 recipe, but thought I would add somemore detail, and post it here as well in case it benefits anyone else:

400ml of sugar.
1 flat teaspoon of yeast (I used bread yeast from sainsburies). 
2L bottle

Mix the sugar in hot water so it melts and you get a syrup. I used boiling water and pyrex dish.

Add some cold water to cool it down (otherwise you will melt the 2l bottle   ) and pour it into the 2 litre bottle. 
Then add more water to the bottle unti it is full - but not right to the top leave 2 or 3inches, as it expands when it 'brews'.

Add the yeast to the bottle. Put the lid on and shake it really thoroughly. 

Mix done    

Insert airline tubing into the lid of the bottle.  Keep it airtight or the CO2 will leak out of here (I used a ring of blu tac   ).

Insert other end of airlne tubing into fish tank.  Make sure you have a valve on the tubing otherwise the tank water will siphon into the CO2 bottle.

Although it starts producing CO2 near enough straight away it takes a while for the pressure to build up sufficiently.... mine took up to a week to really start kicking out co2. If you take the lid off to have a look you will let the pressure out. So be patient!

After one week mine then gave good co2 for 2 weeks then petered out over the third week. I had two bottles spaced 2 weeks apart and it worked well. 

You can tweak the mix to your preference... more sugar may last longer, more yeast gives out more CO2, and various combinations of.


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## gratts (3 Mar 2009)

Cheers Matt - made a bottle last night and it's bubbling away nicely. Just need to track down some tube to make my diffuser


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## a1Matt (4 Mar 2009)

That is good news, I am glad it is all working OK    (I have not forgotten about trying to dig up some pics of my old reactor, just not had time yet.)


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## beeky (9 Mar 2009)

I use just one 2l coke bottle on my 160l and 1/2 tsp yeast. I use a pot of dried yeast from Sainsburys, rather than the sachets as it's a lot cheaper, although you have to store it in the fridge. I don't know how much sugar I just fill half way up a pot I've got!

I bought a kit ages ago that came with the sugar solution as a gel in a bottle that is supposed to be replaced. The cap and tube that came with it fits a coke bottle so that's what I use now.


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