Diy Co2 Not Working Properly

[kuzyaburst]

I made a DIY CO2 thing, with a 2liter coke bottle, smaller mineral water bottle, and tubing. For the recipe I used 1 cup of water + 1 tsp yeast, 2 cups of sugar,, 1/4 tsp baking soda, the water was 3 inches from the top of the bottle. I shook it up and waited 2 hrs. I had water in the mineral water bottle. The problem is that the CO2 IS being produced but it doesn't have enough pressure to go into the tank water, (I don't have a check valve yet) so the tank water occasionally flows back into the bottles and it's a disaster from there. I'm pretty sure I did everything correctly and the setup is good but for some reason the co2 just doesn't have enough pressure to go through the water and into the tank.(I have a 36g tank) What did I do wrong?

 

[Ch4rlie]

Hmm, am not familiar with the yeast Co2 method am afraid. I use pressurised Co2

 
But the set up principle is basically the same, check all connection joints with soapy water to be sure there are no leaks and making sure all connections are correct etc, common sense stuff really. The addition of non return valves may help a little to stop the pressure from going back into the bottle.
 
Also do check the diffuser, sometimes they need a LOT of pressure to enable co2 to start going through so perhaps checking the diffuser may help.
 
Other than that, i do not know how to increase pressure with this co2 yeast method, am assuming you've probably read the yeast Co2 Method article for clues or tips.
 
http/www.fishforums.net/index.php?/topic/341090-the-yeast-co2-method/

 

[daizeUK]

I agree with Charlie.  The problem will either be a leak (which you can check with dabbing a bit of water and a little washing up liquid around joins to see where it bubbles) or a diffusion system that operates under high pressure.  What type of diffuser are you using?
 
Allow up to 48 hours for the yeast reaction to get going and reach maximum pressure.
 
Also... you really do need a check valve as you've discovered.  Ideally you want a check valve between your tank and water scrubber bottle and another check valve between the scrubber and yeast reactor bottle.

FYI you might find that one coke bottle is not sufficient for a 36g tank.  Adding more coke bottles will help to smooth out fluctuations in CO2 production (i.e. you stagger refilling the bottles so that production remains more or less steady).   I use 3-4 coke bottles on my 30g tank, each with 1/4 tsp dried active yeast, 300g (1.5 cups) sugar and 1/2 tsp baking soda.  I don't really recommend yeast at all.  For a tank your size pressurized CO2 would be a much better option.  

 

[kuzyaburst]

I agree with Charlie.  The problem will either be a leak (which you can check with dabbing a bit of water and a little washing up liquid around joins to see where it bubbles) or a diffusion system that operates under high pressure.  What type of diffuser are you using?
 
Allow up to 48 hours for the yeast reaction to get going and reach maximum pressure.
 
Also... you really do need a check valve as you've discovered.

 Ideally you want a check valve between your tank and water scrubber bottle and another check valve between the scrubber and yeast reactor bottle.

FYI you might find that one coke bottle is not sufficient for a 36g tank.  Adding more coke bottles will help to smooth out fluctuations in CO2 production (i.e. you stagger refilling the bottles so that production remains more or less steady).   I use 3-4 coke bottles on my 30g tank, each with 1/4 tsp dried active yeast, 300g (1.5 cups) sugar and 1/2 tsp baking soda.  I don't really recommend yeast at all.  For a tank your size pressurized CO2 would be a much better option.  

I bought a diffuser today with a check valve inside, the diffuser is called "Aquatek 3 in 1 Diffuser" I saw many good reviews on it so I wanted to try it out. I put it on today and fixed some leaks (there were 3 leaks on the bottle cap). I hope in a couple hours the pressure will build up and start pushing the gas into the diffuser. By the 3 bottles what do you mean? How did you set that up? Are the 3 bottles connected to the smaller one, and the small one to the tank? It sounds interesting and I might try it, of course once I get this one to work.

 

[daizeUK]

Yes I mean that the three coke (yeast) bottles are connected to the smaller scrubber bottle, using Y-junctions or T-junctions to branch the tubing.  Each coke bottle should ideally have its own check valve in addition to the one in your diffuser.
 
Each bottle will last for roughly 3 weeks so you change one bottle each week to avoid huge dips and peaks in CO2 production.  Fluctuating CO2 is a recipe for Black Brush Algae and this is the reason I wouldn't advise the yeast method if you can possibly avoid it.
 
Here is a pic of my setup showing the check valves and junctions to connect the large bottles to the smaller one.
 

 

[kuzyaburst]

Yes I mean that the three coke (yeast) bottles are connected to the smaller scrubber bottle, using Y-junctions or T-junctions to branch the tubing.  Each coke bottle should ideally have its own check valve in addition to the one in your diffuser.
 
Each bottle will last for roughly 3 weeks so you change one bottle each week to avoid huge dips and peaks in CO2 production.  Fluctuating CO2 is a recipe for Black Brush Algae and this is the reason I wouldn't advise the yeast method if you can possibly avoid it.
 
Here is a pic of my setup showing the check valves and junctions to connect the large bottles to the smaller one.
 

Oh wow it looks really nice! I'm going to try this out I finally got mine to start pumping the co2 into the tank. 

 

[daizeUK]

Good, finding and fixing the leaks did the trick!  Depending on how well you drilled the holes and how snugly the tubes fit you may need to be careful when moving the bottles around to avoid tugging the tubes and springing more leaks.  Superglue is a good sealant for this though.

 

[dave840f1]

I use the same system but I did not use the original bottle tops I got the tops off eBay that have the screw down clamps (For want of a better word). No leaks from day one. My tanks also heavily planted, sorry I don't know how to download photos.

 

[daizeUK]

That sounds like a good idea.  I  had way too much trouble dealing with leaks from DIY bottle tops.

 

[Ch4rlie]

I use the same system but I did not use the original bottle tops I got the tops off eBay that have the screw down clamps (For want of a better word). No leaks from day one. My tanks also heavily planted, sorry I don't know how to download photos.

 
Have you got a picture of this by any chance, I'd like to see just out of curiousity.
 
To download pics, try this -
 
http/www.fishforum...tures-to-forum/

 

[dave840f1]

Sorry for the delay I've been away for a couple of days, tried to download pic. But no joy anyway try eBay item number 191225795984 this will take you to them. They have gone up in price now when I purchased them they were only £0.99 + free postage.