CO2 Injection

[djlen]

CO2 Injection

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Owing to the fact that one our members recently lost a number of fish, due to improper use of CO2, I felt a need to post on this subject, regarding the dangers as well as the attributes of using gas in the planted tank.
Shortly after reading his post I was visiting another site (myfishtank.net) and read what I consider to be a very well written and thought out article on this subject by Kevin Batchelor, AKA: '1979camaro'.

Kevin's article:

While there are many different opinions about lighting, fertilization, and substrate, carbon dioxide is considered to be a necessity by most, if not all, aquascapers who are interested in creating dynamic, heavily planted environments. Certainly, success can be had without the addition of CO2, however the results will not be the dazzling aquariums which inspire so many aquarists to undertake a planted setup.

Carbon dioxide is the most critical plant nutrient (light not being a nutrient). Any stocked aquarium will provide plants with some CO2 (due to the respiration of aerobic organism, aka fish and other critters), and while this minute amount is often sufficient to maintain a few healthy plants, it can in no way fulfill the needs of a densely planted aquarium. When CO2 is not present in sufficient quantity plants grow very slowly and will tend to stay smaller. Furthermore, biogenic decalcification can occur; this is, essentially, a last ditch effort by the plants to obtain CO2 by breaking down the salts in the aquarium water. As this process occurs, the pH level can raise a couple points in a fairly short period of time. This alone is stressful enough for the fish, but the problem worsens when the lights are turned off. When photosynthesis stops at night, the plants will stop breaking down these salts and the pH will drop rapidly. This fluctuation is very harmful for the fish, but there is a simple remedy: provide the plants with a source of dissolved CO2.

So, now that the ill effects of carbon dioxide deficiency have been presented, the question becomes: how does one provide dissolved CO2? When the volume of water is large it is very difficult to supply and regulate the amount of CO2 necessary without a pressurized system and a regulator. A good analogy is a scuba divers tank. The bottle valve is always on and the regulator adjusts how much CO2 is injected into the water. This type of setup can be fairly costly, however it is certainly the most reliable means of controlling (and adjusting with ease) the amount of CO2 in the water. For small tanks, particularly those of 55 gallons and smaller, Do-It-Yourself (DIY) CO2 injection is often the cheapest solution. DIY CO2 is quite cheap. Aftermarket products are available to the person wary of actually doing the DIY themselves, however there is virtually no difference between these products and a simple DIY CO2 reactor and diffuser. The drawback to a DIY setup is the relative difficulty of adjusting the amount of CO2 injected into the aquarium. However, most people with small aquariums find that a DIY system works well, and the lack of regulation does not generally cause a problem with over-dosing. A simple DIY reactor can be built for around $10, considerably less than a pressurized system.

Building a DIY CO2 reactor is a great first project. It is relatively straightforward; all one needs is a 2L bottle, aquarium silicone, airline tubing (many people use silicone tubing because it degrades less quickly), a check valve, and something to diffuse the bubbles (cotton balls and air stones both work, as will most anything with a fine mesh; some people use a bell type diffuser). First, measure the diameter of the airline tubing (it is usually 1/4", but there are other sizes). Next, using a power drill or Dremel tool drill a hole into the plastic cap of the 2L bottle. Frequently, the soft plastic seal on the inside of the cap must be removed at this point. The hole should be just slightly smaller than the diameter of the tube to help establish a tight seal. Insert the tubing from the top of the cap into the hole until it extends at least one inch through the underside. At this point, seal around the tubing on both sides with silicone aquarium sealant. It is important to do a good job filling all the crevices and gaps or else the CO2 will leak. Read the directions on the tube to see how long it needs to fully set; a day is a good estimate, however waiting an extra night will not hurt. If the sealant is not fully cured it simply will not hold, and that can be very frustrating. At some point in the tubing many people place a check valve. This is a good precautionary measure to prevent water from siphoning back into the bottle, especially if the reactor will be below the water level; a check valve is, however, by no means a necessary component of the DIY CO2 reactor. Two or more bottles can be connected together through the use of a T connector; brass is best because it will not dissolve as quickly as hard plastic; in theory, as many bottles as are necessary can be connected together. The placement of the tube outlet is really a matter of personal choice. Many people like to put it in the filter intake because this allows the CO2 more time to mix into the water; really, anywhere in the tank will work, though lower is generally better because the bubbles will have more time to dissolve.

So, now there is a beautiful DIY CO2 reactor sitting under the tank, but it is empty. There is one general formula for creating the CO2, but there are many different opinions on the proper measurements for the ingredients. One which has been successful for many people is a combination of 3 cups of white granulated sugar, 1 teaspoon of baking soda, and 1 teaspoon of yeast. The yeast consumes the sugar which uses the oxygen in the bottle and releases CO2 as a by product of this process. Combine these three ingredients in the bottle and fill it with lukewarm water to the area where the bottle begins to slope inward. Though it is not necessary, it is not a bad idea to shake the bottle up and try to dissolve as much of the sugar as possible. All that is left is to screw the bottle into the cap and watch the bubbles begin. Usually this process takes 10-30 minutes with full strength being reached within a few hours, however do not fear if it takes a little longer. Certainly, however, if no bubbles appear within 24 hours there is a problem and any seals should be checked. Most often the escaping CO2 can be heard hissing around the area where it is leaking.

A noticeable improvement in the growth rate of the plants should be visible within a few days, however certain things can prevent the CO2 from having its full effect. The most frequent problem is surface agitation; surface movement facilitates the release of dissolved CO2 into the air. This is particularly problematic with hang on the back filters when the water level is not raised to the edge of the filter outlet. Ideally, a canister filter should be used, however many times this is not an option, nor is it truly necessary; a daily check of the water level and topping off when required should be sufficient to prevent major problems.

Maintaining the appropriate amount of dissolved CO2 is an important part of a planted aquarium. Most planted aquariums require around 1 gram of dissolved CO2 for every 25 gallons of water. By comparing the pH value of the water and the carbonate hardness (KH) as determined through test kits it is easy to derive the milligrams per quart of CO2 through the use of a simple flow chart which is available from many sources, one of which is here: http://www.aquabotanic.com/charts.htm

Carbon dioxide is still just one part of the equation; the amount of CO2 necessary varies with the number of plants, fish, and amount of lighting. Experimentation is an important part of achieving the type of planted tank which can win praise and admiration, as well as provide satisfaction to those who view it. While it may seem complicated, it really is quite accessible with a fair amount of research, forethought, and patience.

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I will add one comment to the above:
Before contemplating the use of CO2 in your aquarium please know your water's kH. If it is not, at minimum - 3.0dH, it should be raised before injecting gas.

Len
__________________
Have Discs - Will Travel

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[djlen]

Here's an excellent article on water chemistry:
http://www.drhelm.com/aquarium/chemistry.html

Len
__________________
Have Discs - Will Travel

[djlen]

ALTERNATE RECIPE FOR DIY CO2

2 CUPS WATER
2 CUPS SUGAR
1/4 TSPN YEAST
1/4 CUP TEPID WATER
WITH THIS EXTRA 1/4 CUP OF WATER - ADD 1/4 TSP OF YEAST
AND STIR IN A SMALL CUP. STIR YEAST UNTIL IT IS NO LONGER
IN CLUMPS, BUT INSTEAD A SMOOTH CREAMY TAN LIQUID. THEN
ADD A FEW PINCHES OF SUGAR AND VIGOROUSLY MIX THE YEAST LIQUID
UP MAKING LOTS OF BUBBLES. YOU WANT TO GET OXYGEN IN THERE TO
GET THE YEAST GOING. ONCE THIS IS DONE, LET THE MIXTURE STAND
FOR 10 MINUTES. THEN TAKE YOUR FUNNEL IN HAND, OPEN THE BOTTLE
YOU'VE ALREADY PREPARED, AND POUR IN YOUR YEAST CULTURE.
THIS ADDITION TO THE RECIPE SHOULD GET THE REACTOR WORKING QUICKER
AND LASTING LONGER (APPROX. 16 DAYS) EVEN THOUGH IT CALLS FOR LESS
YEAST.
THERE IS EVIDENCE THAT YEAST MIXTURES LAST LONGER IF YOU DECREASE
THE AMOUNT OF YEAST, AND CONVERSELY LAST SHORTER PERIODS OF TIME WITH
MORE YEAST. LOWER YEAST ALSO MEANS LESS CO2 PRODUCED PER MINUTE, BUT
PRODUCES MORE CONSISTENTLY OVER TIME. HIGHER YEAST LEVELS WILL
PRODUCE AN INITIAL BURST OF CO2 PRODUCTION WITH A GRADUALLY DECLINING
PRODUCTION OVER TIME.

********Jell-O Method for DIY CO2*******

Add 2 packs (4 serving size) of Jello into an empty clean 2L soda bottle.
Add 2 cups of boiling water and mix so that the jello fully disolves.
Add 2 cups of sugar and mix the solution again to disolve the sugar.
Add 2 cups of cold water and mix the solution again.
Store in the refrigerator overnight or until jello sets.
The next day, add one cup of room temperature water.
Add 1/4 TSP of yeast and a pinch of baking soda.
Cap the bottle and wait for it to go...

The sugar yeast method lasts about 2 weeks...
this lasts about 4-5 weeks for most people

Useful article: http://www.thekrib.com/Plants/CO2/
Knox unflavored gelatin is less exepensive than Raspberry Jell-o.

Len

[nursie]

I'd like to add to Harlock's request. When i was starting up pressurized CO2...and I'm still learning, I looked everywhere I could think of for an east step by step guide on what equipment I needed, and a diagram from cannister to tank what I needed, also what tests you need to run and how the heck do you check CO2 level.
What's the difference between a diffuser and an reactor..what's better?

[djlen]

I'm going to start putting together a list of sites that are reliable sources for parts pertaining to both pressurized and DIY CO2.
I also want to include direction and information that is understandable to the experienced and the newbie in our community.
In addition I'm asking those who know of sources and sites with understandable info. to contribute what they have.

Here is a list that I will continue to expand over time:
Parts:
http://www.aquariumplants.com/CO2_Accessories_s/50.htm

Instruction:
DIY/CO2:
http://www.qsl.net/w2wdx/aquaria/diyco2.html#6
http://www.thekrib.com/Plants/CO2/

How to measure CO2/ppm:
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

Len

[paul]

Here's a site with some info on injection

http://www.wcf.com/co2iron/

I put that link on there because it has a good picture of the Eheim C02 diffuser. I'm not sure it's the best price though. The good thing is that the guy carries everything you need and will answer questions. Although I've never used his product that he claims is a good replacement for a regulator (It's been about 8 years since I bought from him). It is probably fine though, as he's a reputable seller.

Basically, the way I do it is: C02 tank -> regulator (it doesn't have to be a dual gauge one, that is a myth, I've used a single gauge one) -> adapter for tubing -> Eheim defuser.

There's a valve on the defuser that restricts the flow of CO2. There's a porous glass disk on top that basically acts like an airstone. Put a powerhead near the bubble flow for best circulation.

IMO, this is the simpliest and probably the cheapest way to inject pressurized C02

[jhj]

Regular airline tubing is not suitable for CO2, it gets crusty and turns into mush. Avoid at all cost.

Silicone is thought of as an acceptable alternative. Although it will not get crusty, but it does loose 6% of CO2 for every foot, so if you have 5 feet of silicone tubing, your loss rate is 30%.

The best and most efficent CO2 tubing is polyurethane. Clippard manufactures this tubing, it is the first one on this link. Simply select the size (regular aquarium use CO2 tubing is 1/4"OD and 1/8" ID)and color, find a dealer in your area and order it through them to avoid the shipping and handlinr charge.

Check out this CO2 tubing comparision chart and look at the permeability rates of Silicone vs. Polyurethane

[Galaxie]

I was curious, how fast should the CO2 come out of the air tube? Will there be a steady stream of bubbles or will they be slow enough to count?

If I decide to turn off the CO2 at night, how should I stop it? Plugging the bottle will just cause an explosion I assume. Can I simply aerate at night to counteract the CO2....which isn't really needed when the lights aren't on.

Thx

[bencozzy]

djlen-i tried the jello recipe and it seems to be working really well but the jello never set for me is that a problem? i foolowed the recipe exactly did i do something wrong?

thanks

[sploke]

One reason the jello recipe works better/longer than the regular sugar recipe is that the jello contains stuff other than sugar that acts as nutrients for the yeast. I brew my own beer and wine and have learned a lot about what it takes to get yeast to work properly. In the regualr sugar recipe, you can almost double its life by adding a teaspoon or so of molasses. The yeast needs mainly sugar to live, but it also requires a lot of other nutrients to thrive and produce lots of CO2. I have DIY on my 10gal, I use 1c sugar, a tsp of molasses, fill it up half way with warm water, use about 1/4 tsp of yeast, and it keeps my tank at 18-25ppm CO2 for almost a full month. Just some food for thought for those of you looking to extend the life of a DIy batch.

[Galaxie]

I have had my DIY unit up and running for about 16 hours now (overnight).

Before setup, my dKH was 3.0 and pH was 7.0.
Per the calculator here, http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htmthis gives me 9ppm CO2... which is normal considering its a 37g tank with an 11 inch pleco, 3 small flagfish & one small Amazon Sword.

12 hours after setup (no light) my dKH is 4.0 and the pH dropped slightly to 6.8. This calculates out to 19ppm CO2.

So, it appears the system is working. The fish seem unaffected.

After 12 hours of light (one fully day/night cycle), I was wondering, what should I expect? Ideally, will the pH and dkH stabilize to hold the CO2 at 19ppm?

[bencozzy]

i had to add the jello and sugar at the same time to get it to harden.

im trying the jello mix with molasses to see what it does

[VampyricSeductress]

thanks to reading this im ready CO2

[djlen]

Here is a nice, easy to understand nutrient calculator called the Fertilator.
I suggest saving a shortcut to it, to your desktop for easy access:

Aquatic Plant Central

If you have additional questions on this or any other topic in this thread feel free to PM me and I'll try to answer them. I don't monitor this thread as often as I should.

Len

[bencozzy]

ok forgot to post my results from my jell-o molasses co2 batch

got a consistent output for 6 weeks when i let the culture go anaerobic, if i kept it aerobic i got a good 7 weeks out of it. i could have probably pushed these cultures another 2 weeks easily.

as for dosing i followed the jello recipe as above and i either added half teaspoon molasses after jell-o set, half tspn before and then another half tspn after of molasses, or just one tspn after jello sets. all gave similar results.

ben

[TwoTankAmin]

When I first got into plants and co2 injection I got a lot of help from a gent named Jared Weinberger. He has a site, which unfortuantely has some dead links last I looked, but he has some nice photos and diagrams of his co2 set up:

Pressurized CO2 Setup for a Planted Aquarium
and
Tank Setup

The main site URL is Aquatic Plants: Planted-Tank Resources

[bencozzy]

request- can we get a list of info. on diffusers there are a ton to choose from which ones work what doesnt how effective are they etc.