How To Make A Diy Co2 Kit

aaronc

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Hi All

After a request I have decided to put together a quick guide on how to make a DIY CO2 kit. George Farmer has kindly told us all how to make our own yeast mix here - http://www.fishforums.net/Nutrafin-Co2-Bas...de-t164548.html

What you will need:

1 x 2 Litre Pop Bottle - Clean
1 x 500ml Pop Bottle - Clean
1 x Non Return/Check Valve
2-3m CO2 Imperbeable/Resistant Airline Tubing
Pliers
Drill
Scissors
5ml Drill bit - this may vary depending on airline size, however 5ml bit is ideal for 6ml airline

Here at the parts ready to go.

whatyouneed.jpg

There is a t vavle in this picture which isn't strichtly necesary unless you are using more than one fermentation bottle.

Step 1 - Drill a 5ml (if using standard airline) hole in the top of the 2 litre bottle lid and 2 x 5ml holes in the top of the 500ml bottle lid, as shown below. NB It is very important that you get the right numbers of holes in the right lid, as you will see shortly.

lid_blue.jpg


lid_pink.jpg



Step 2 - Cut your airline into 2 lengths. One needs to go from one bottle to the other and will only need to be around 1ft in length. The other needs to go from the smaller bottle to your tank, so you will need to calculate this length yourself.

It is worth considering at this point where to situate your kit. Above the tank is preferable as then there is little chance of the system creating a syphoning effect and draining the tank. However, if you would rather keep the kit below the tank, which is often tidier then make sure you use a check valve between the 500ml bottle and the tank. This is very important so don't forget it.

Step 3 - Take the shorter length of cable and cut the end in half, about 1 inch into the tube. Now do the same on the other end of this tube and to one end of the longer tube. This will make it easier to thread the tube through the hole, which is 1ml smaller than the tube.

If you want a super tight fit you can put some silicone sealant in the hole before threading the airline through, this will help create a stronger seal.

Here is a picture, sorry about the quality, don't have a macro lense, but it should give you an idea of what I mean.

airline_splice.jpg


Step 4 - At this point I would reccomend filling a mug with boiling water, this will make this job much easier.

Now dip one end of the short tube into the boiling water, then feed it through one of the holes in the 500ml bottle lid (which in this instance is blue). You will find that the whole tube won't fit through, if this is the case simply use your pliers to pull on end of the airline until it comes through. The reason we cut the airline in half earlier is so that the initial inch of the airline pulls through easily.

Now dip the other end of this tube into the water and repeat the process, instead however feeding this end into the 2l bottle top, in this instance pink.

Now feed the end of the long tube into the remaining hole in the blue lid.

Once this is complete trim off the spliced ends of the tubes so they are back to normal.

Step 5 - Now, (are you bored yet ;) ) we need to trim the airlines that go through the lids. The airline that comes from the 2l lid needs to be trimmed fairly flush to the bottom of the lid, leave about 1cm protruding from the bottom of the lid.

At the other end of this tube you need around 3-5 inches of airline tube remaining, pull more through the hole if needs be. NB - If you are intending to use the second bottle as a bubble counter then you need to make sure you leave this slack.

Now, the end of the long airline that goes into the blue lid needs to be trimmed to within about 1cm of the lid.

Trimming the airlines in this way will ensure that no yeast mixture ends up in your tank.

There are two pictures below, although in actual fact I could take a bit of more off of these ;)


airline_in_blue.jpg


airline_in_pink_lid.jpg



That is about it for this simple CO2 kit, you should no have something that looks a little like this

finished_thing.jpg



Some notes...

Yeast Mixture - I am not entirely sure how much to put in a 2 litre bottle as I use nutrafin kits - Maybe some one could let me know what quanities they use and I will update this.

Modifications - This guide will get you set up with a basic kit but there are a variety of modifications that can be made.

- Addition of a 'venting off' valve - if you want to be able to choose when you inject CO2 you could use a Tvavle and take a line off of the main line just before the check valve. Simply place an 'on/off' valve on the end of this and open it when you want to vent off the C02. The CO2 will take this route as it is easier than trying to push through the check valve. In actual fact this is not really needed as yeast based kits can be left on 24/7 usually.

- Multiple fermentation bottles - It is a good idea to use this method as it results in a more stable CO2 level if the bottles are changed alternately. Simply make another 2 litre bottle as show above and use a t junction to tie into the the main line, making sure it goes before the 500ml bottle.

- Diffusors - I have delibrately not covered these as they are not my forte. You could use a ceramic diffusor, or if you are on a budget then a ceramic airstome will get you started.

EDIT - When using diffusors It is necesary to seal all joins etc with silicone or something similar. Diffusors place the whole system under much more pressure than ladders. This can in turn cause joins to fail and the CO2 mixture to leak. In truth I would reccomend sealing all joins regardless of the method you use to diffuse CO2, just to be sure.

- Bubble Counter - Fill the 500ml bottle to about an inch above the bottom of the longer airline with water, you now have a bubble counter :)

That's it from me.

Hope this helps someone

Aaron

PS - The author accepts no liability for co2 based explosions lol
 
Aaron.

Don't mean to step on your toes here, but a much better seal is gained when drilling a hole just smaller that an airline connector (i.e. the straight version of your T-piece)

Then force the hose connector into the hole, silicon the top and bottom.

This also means you can disconect the tube from the bottle at any time with no problem.

This doesn't show it too well, but this was my kit before I succumbed to pressurised.

DIYSetup.jpg


Andy
 
I agree Andy

This is just a tutorial for a bog standard basic kit for some one who doesn't have access to extra parts.

I would use the straight airline connectors and glue them in place to :)

I will update the tutorial, and add that point in the modifications bit

Thanks
Aaron
 
I like to make the fitting too tight aswell as putting silicone at the same point too. When using the ceramic diffusers, they require high pressure. Therefore they put a lot of stress on the whole DIY CO2 kit and when i didnt have silicon on 1 part, there was evidently some leaking, even though i had a really tight fit. I also used a urine sample bottle as my filter lol. As its smaller, it means that the CO2 can reach pressure sooner.

Also you forgot to mention that CO2 resistant tubing is reccommended. (Even though by looks, it seems you used CO2 resistant tubing in your guide)

Good attempt! and i liked your tip with boiling water. Didnt think of that ;)

edit... lol, you are 1 step ahead of me ;)
 
Thanks for this excellent, concise guide. It's exactly what I need for my first attempt to follow shortly. If my house blows up from the pressure, my lawyers will be in touch :rolleyes:
 
Excellent work Aaronc, cant say I would ever use yeast again having switched to pressurised, however this is an excellent guide :) Should have been done ages ago.

Sam
 
Thanks for this helpful thread, Aaron. I've already ordered a couple of diffusers, some CO2 airline and bubble counters off t'internet. I'm currently drinking as much fizzy drink as possible in order to get enough bottles.

I'm planning one 2 litre bottle for my 80 litre tank and 2 more going into one diffuser for my 240 litre tank. I'll let you know how I get on. Does anybody have a fairly accurate idea of how much sugar and yeast to put into a 2 litre bottle? Do you fill the water level practically to the top and does the amount you need to add vary? i.e. more yeast for a larger tank (to make more bubbles per minute to dose the higher volume of water with the correct level of CO2)? (hope that makes sense to others?)

My understanding of some of this is still rather sketchy!

Andy.
 
Excellent. I've been pondering this lately after it was suggested on my journal to try DIY... I have a 2ltr bottle ready and waiting... Now to find some CO2 resistant airline :|

Had a thought. You could substitute the 500ml bubble counter bottle for something smaller, like a panda pops style bottle if you wanted something smaller and more subtle. Mind, a 2ltre bottle isn't exactly subtle :D
 
Hi Dev

Yeah you can swap it. The reason I use one is to catch all the yeast mixture that escapes the bottles and would otherwise flow into the tank. This doesn't happen to me so much now as I have split the yeast between a nutrafin canister and a 1litre bottle (2l bottle wouldnt fit in my tank cupboard lol).

If I had used the smaller bottles, ie a urine test bottle then the yeast mixture would soon have filled it and got into the tank.

Aaron


PS - I am not using co2 resistant tubing at present. Not sure how importnat it is in a DIY Low pressure system. I still seem to get plenty of co2 in my ladder. Pressure becomes more of an issue when using a diffusor as they subject the whole system to higher pressures

Aaron
 
You shouldn't have pressure issues if you are using a suitable diffusor. You need to research these.

And if you setup the DIY bottles with the correct amount of sugar, yeast and water then you should never get any mixture reaching the tank or at worst just some small amounts very close to the 2Ltr bottle

(I appreciate that you need to experiment with the quantities before geting this right as there are so many different types of yeast and they all react differently)

I used to use 13 dessertspoons of Sugar or 1 tea cup (not mug), 1¼ teaspoons (proper measuring spoons) of the fast acting bread yeast and fill with warm water just above where the bottle starts to curve into the neck

Andy
 
Hey guys. A quick question about yeast... ie, what is the best yeast to get? I've seen "active yeast", "baking yeast", "dried yeast" and some others, are they all the same?

Would this work fine?

Cheers :)
 

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