E N D
1. NACU Nature Aquarium Club of Utah
August 28th 2007
Topic of discussion: DIY CO2
3. Why add CO2? There is already CO2 in the water. Why do we need to add more?
Increase plant health
Plants need Carbon and CO2 is the most common source
Even at low levels of light (1.5 wpg) CO2 will increase the health and growth rates of your plants
Fighting algae
Healthier, faster growing plants will help keep the algae down
4. Do I need CO2? Fish give off relatively little CO2
Light intensity is usually the deciding factor
CO2 is optional under 2wpg and mandatory above 2wpg
Nothing magical happens at 2wpg it is just a general rule-of-thumb
Even under 2wpg, additional CO2 will help your plants
5. What is DIY CO2? Do It Yourself CO2:
Yeast is mixed with sugar and water
The yeast consumes the sugar and produces alcohol and CO2
The CO2 is then plumbed into the aquarium and dissolved into the water
6. Alternatives to DIY CO2 Pressurized systems
Flourish Excel
Lower light
Lots of algae
7. Alternative to DIY: Pressurized system Pros:
Cheap to maintain
A CO2 refill is about $10 and lasts about 6 month
pH regulators (optional on pressurized system) will keep your CO2 levels very consistent
Very little maintenance
Set the pH (or timer), adjust the bubble rate and forget it
Cons:
Very expensive initially
8. Alternative to DIY CO2:Flourish Excel Pros:
Easy, simple and straight forward
Excel has other uses also
Cons:
Not as effective as real CO2
Can be expensive on larger tanks
9. Advantages of DIY CO2 Inexpensive
Only costs a few dollars
Very customizable / expandable
10. Disadvantages of DIY CO2 Difficult to regulate CO2 levels in your tank
Inconsistent CO2 production from
Temperature fluctuations
Bacteria contaminating the yeast mixture
High maintenance
Lots of potential problems
11. Parts of a DIY CO2 system Yeast mixture
CO2 generator (the container holding the yeast mixture)
Plumbing
CO2 diffuser (also call a reactor)
Bubble counter (some call it a scrubber)
12. Parts of a DIY CO2 system:Yeast mixture There are many different recipes
Basic recipe for a 2 Liter bottle:
2 cups sugar
tsp yeast
just under 2 Liters of water
Scale the recipe up or down for different sized containers
13. Parts of a DIY CO2 system:Yeast mixture Recipe alternatives:
Substitute cup sugar for cup molasses
Add 1 tsp baking soda
This is done to buffer the water
Utah's water already has plenty of buffers
Add 1Tbl powdered protein drink
The standard recipe will usually work just fine
14. Parts of a DIY CO2 system:Yeast mixture There are lots of different yeast choices
CO2 production usually slows down and stops because of elevated alcohol levels
Baker's yeast will work fine, but other yeasts are resistant to higher alcohol levels, which helps the mixture last longer
Wine and champagne yeasts work very well
My favorite: Premier Cuvee
15. Parts of a DIY CO2 system:Yeast mixture Two options to mixing a new batch
Fresh, clean start
Mix the sugar with boiling water and pour into generator bottle. Allow it to cool.
In a bowl, mix yeast and luke-warm water and a little sugar
Stir vigorously to aerate the yeast mixture and let it stand for 10 minutes
Then add the active yeast to the generator bottle
16. Parts of a DIY CO2 system:Yeast mixture Option 2: reuse the old yeast
Simply pour most of the water out of the expired generator bottle
Some of the yeast must remain in the bottle
Add 2 cups sugar and refill generator with luke-warm water
Shake to mix
Connect the generator back to the plumbing
17. Parts of a DIY CO2 system:Yeast mixture I prefer to reuse the old yeast
Recycling the yeast increases the risk that your yeast mixture will get contaminated by bacteria
But it is a lot less work!
Recycling the yeast also uses less of the expensive wine yeast
18. Parts of a DIY CO2 system:Yeast mixture There are MANY different way to mix/prepare the yeast mixture
Everyone seems to do it a little differently
Experiment and find out what works best for you
19. Parts of a DIY CO2 system:Yeast mixture Final notes on Yeast mixture
Yeast generates CO2 and in a closed system the pressure can build up and explode your generator (big mess!)
An extra cap is nice so that you can shake the yeast mixture to mix it but be very sure NOT to leave the cap on
20. Parts of a DIY CO2 system:Generator bottles The most commonly used bottle for the CO2 generator is 2 Liter soda bottles
Other bottles may be used as long as they are airtight
It is common for people to use 2 generator bottles so that there is no interruption in CO2 production when 1 bottle is replaced
I like to have 2 bottles and replace 1 of them every 3 to 4 weeks
21. Parts of a DIY CO2 system:Plumbing Choice of air tubing:
Standard air tubing is a poor choice
Silicone tubing works well and is cheap and easy to find
Special CO2 tubing will lose less CO2 from seeping out of the tube walls
But it is quite expensive and hard to find
22. Parts of a DIY CO2 system:Plumbing Attaching the air hoses to the bottles can be problematic
A poor connection will lead to leeks
Good options:
Bulkhead fittings make a good mechanical connection
Where to find?
www.towerhobbies.com
A little pricey
Provide a good strong mechanical seal
23. Parts of a DIY CO2 system:Plumbing Good options:
Rubber stoppers
These also provide a good strong mechanical seal
If a blockage occurs, the stopper will pop out before the generator explodes. (This is only an assumption I have not yet tested this but am looking forward to it!)
They are a little cheaper than bulkhead fitting
Some stoppers come with holes in them already but some do not. Adding holes can be difficult
24. Parts of a DIY CO2 system:Plumbing Rubber stoppers continued
Getting the tubing through the stopper
Using a pair of scissors, cut a 2 portion of the tube in half lengthwise
You can then push the halved portion of the tube through the hole in the stopper
Using a pair of pliers, grip the halved portion of the tube and pull more of the tube through the hole
Then cut off the halved portion of the tube
25. Parts of a DIY CO2 system:Plumbing Rubber stoppers continued
What size rubber stopper to get?
For a 2 Liter bottle size # 4
For a 1 Liter bottle (wide mouth same as the 3 Liter bottle) size # 6 or 6.5
Stoppers are often available with 0, 1 or 2 hole
Ebay is a good source
26. Parts of a DIY CO2 system:Plumbing Glues can also be used to attach the airline to the bottle
Drill a hole in the lid smaller than the tube and squeeze the tube through
Then seal the tube in with some form of glue
What glues will work?
Glued joints are a common source of leeks
27. Parts of a DIY CO2 system:Diffuser Simple airstone
Cheap, simple and easy
Will waste a LOT of CO2
Glass diffusers
Create a very fine mist of CO2
May need more pressure than DIY can supply
Usually cost less than a powered reactor
28. Parts of a DIY CO2 system:Diffuser Existing powerhead or filter
CO2 line is fed straight into the inlet of the filter or powerhead where the CO2 bubbles are broken up and dissolved into the water
Very cheap and easy
Can be noisy and bad for the filter
Reducing the size of the bubbles helps both noise and filter wear
29. Parts of a DIY CO2 system:Diffuser Powered / in-line diffuser
Usually very efficient (very little loss of CO2)
Can handle large amounts of CO2
Can be bulky / ugly in the aquarium
Can be fairly expensive to buy
Venturi effect can suck yeast mixture into your tank
Using rigid generator bottles (like Gatorade bottles) can prevent this from happening
30. Parts of a DIY CO2 system:Diffuser Bell diffusers (my favorite)
Very cheap (free sometimes)
Stable / consistent CO2 levels
Diffusion rate changes very little
Serves as a small CO2 storage tank when changing yeast mixture
31. Parts of a DIY CO2 system:Diffuser Bell diffusers (continued)
Bulky and ugly in the aquarium
May need to be quite large to get enough diffusion
Can lose a lot of CO2
This is what keeps the diffusion rates constant the extra CO2 escapes the diffuser and then the aquarium
32. Parts of a DIY CO2 system:Bubble counter The bubble counter is a separate bottle placed between the generator and the diffuser
The inlet hose (or hoses) are long enough that they are under water
Because the end of the hose is under water, you can see the CO2 bubbles as they come from the generator. This allows you to monitor how much CO2 is being produced by your generator (or generators)
The outlet tube is above the water level
33. Parts of a DIY CO2 system:Bubble counter The bubble counter has another important feature:
The yeast mixture can sometimes get into the airline hoses. If you have a bubble counter/scrubber, the yeast mixture will only get into the bubble counter and not your aquarium
Yeast and sugar in your aquarium can lead to HUGE problems
34. Construction notes Do not shake the generator while the hoses are attached
This can cause the yeast mixture to get into the hoses
Check valves can prevent loss of CO2 when changing the yeast mixture and prevent the hoses from accidentally siphoning the water out of your tank
35. Construction notes Make sure that the generator(s) and bubble counter cannot tip over
Yeast can generate a lot of pressure and cause the generator to explode
Never cap the generator
Keep yeast mixture out of the hoses
It may be a good idea to use some sort of pressure relief system
36. Construction notes Other construction suggestions?
37. Regulating your CO2 levels Timers (helpful for day/night fluctuations):
Can be used for powered reactors
The reactor can be used on the same timer as the lights
Make sure that when the pump is off, the CO2 does not air-lock the pump
Can be used for air pumps when the lights are out
38. Regulating your CO2 levels Bell diffusers (useful for generator output fluctuations from week to week)
This is based on having excess CO2 that just escapes the aquarium
Can be wasteful
39. Other thoughts? Any other thoughts or suggestions?