DIY CO2- the good, the bad, the ugly

I noticed a lot of guys starting to ask about CO2, DIY CO2, cheaper options, the right options, the right amount etc etc with regards to injecting CO2 into a tropical tank. I've done a fair amount of online reading, spoken to a few LPS owners (useless bunch of characters they are!) and would like to share my experience, and advice.

This advice is based on my reading and chatting to people, and not based on my experience (yet) as I have only had a DIY CO2 going for 1 week now.

The first question you need to ask yourself if WHY do you want to add CO2? CO2 is a brilliant addition to a planted aquarium, but only if the following 2 criteria (in my opinion) are met. (1) you have enough light. Let's go back to Grade 6 , or standard 4, basics. Plants convert CO2 into the building blocks of life, i.e Carbon, through the process of photosynthesis. Photosynthesis, as the name suggests ('photo') requires good light, and light of the correct spectrum. As light is made up of varying wavelengths, you need to make sure you have the right TYPE of light as well. Secondly you need enough OXYGEN in order to sustain the current fish in your tank.
Let's face it, adding CO2 to your tank is adding a poisonous gas into your water, and unless you have sufficient oxygen in the water, your fish will suffer the most.

I have learnt 2 valuable lessons in life. The first one is (courtesy of my parents), "If in Doubt, DON'T DO". If you are in doubt as to whether you want to add CO2 or not, then rather don't until you are certain. If you are certain but don't know which system to use, then my second life lesson's comes into play, (courtesy of miss Rory Gilmore of Gilmore Girls!) "Draw up a Pro-Con list!!!!

All CO2's provide the same basic function. To add CO2 to water.

In my reading and chatting to people, there are very few CO2 injectors that are self controlled, meaning, they monitor the water themselves and add only what is necessary. Most CO2 injectors rely on the user regulating the amount of CO2 into the water. Unfortunately to date I have not found any instructions on how much to add, etc etc... which makes it a 'hit and miss' exercise.

Whether you go for a fancy expensive CO2, or the simple DIY CO2, at the end of the day... the amount that needs to be added is up to you!

There are many pros and cons to the DIY CO2... and many aquarists have heart failure if they learn you are using DIY. But I believe that if sufficient precaution is exercised, you can get just as much success out of a DIY as the more expensive injection kits.

When you google DIY CO2, there are any precautions, or worrys that are mentioned that you need to be careful of when doing DIY, and I'd like to share my own ways in which I tried to overcome these concerns.

The main concern with DIY is that it is very difficult to regulate the amount of CO2 being injected. This is true, and unless you take precautions, you will have no idea how much you are adding. What I did was by adding 2 simple devices (cost of R 50.00 total), I am now able to monitor. Putting CO2 through an airstone doesn't work effectively if you wanting to monitor. The bubbles are jut too small, and form a continuous stream of bubbles. I inserted a control valve into my airtubing, and terminated the tubing in a "bubble counter". The bubble counter allows me to count how many bubbles (which are now all the same size and released relatively a the same time), are released into the water. As I have mentioned, I do not know how much bubbles to add, but in order to prevent fluctuations, I just control the amount of bubbles that exit per minute. As the DIY kit starts to run out, I oen the valve a little more to ensure I have the same constant. Then, when I notice that I cannot open any more, I prepare a second bottle, let it stand over night, and connect it the next day.

The second concern is the container it is kept in. CO2 buildup inside the bottle can, in theory, explode the bottle, leaving an amazingly sticky, beer smelling mess all over the place. But let's be real here, a coke bottle is deigned to take a certain amount of pressure... and if your design is good, the bottle won't explode. When I drilled the hole into the bottle cap for the tubing, I used a drill that fits INSIDE the tubing. I then used the very soft flexible tubing, and because it is soft, it creates it's own seal into the bottle cap. Thus I did not need to use silicon to seal it in. I also did not stick the tube in very far, only about 10mm, so if too much pressure is built up, I'll simply pop the tubing off!

So how much CO2 should you add! The 2 million dollar question! Well, I am yet to find that out, and simply add what I think is right. It'll take a few weeks to get the correct amount for your specific tank... obviously you need to take water pH and hardness into account. What I have done this week is made sure that my pH remains constant. (Yes, it did drop to 6.8, but it now remains constant), made sure that the fish are happy, (they are actually a lot more energetic and happier now with the CO2 being put in than before! - altho I think it's because before I have pH of 8.2!). And now I monitor the plant growth.

So (1) I first check that my water has room to drop in pH... if your pH is at 6.2, adding CO2 in theory could drop it too low for your fish to live!
(2) I make sure my fish are happy, not gasping, and still living as normal behaviour.
(3) I watch for plant growth. My tank over the last week has shown super signs of growth, and I am very happy with the level of CO2 I am added, even though I do not actually KNOW how much I am adding!

My plants are growing, my pH is stable at a very good level for my fish, and my fish are very very happy. (to the point that I have my first successful batch of fry!)

Building CO2 can be very successful, if your conditions require CO2, and if you prepared to put the time and effort into your tank. Also bear in mind that putting a CO2 system in for 1 lonely plant is a waste!!

Adding CO2 will stimulate growth, meaning bigger plants, resulting in more oxygen. In theory you should add more CO2 as the plants grow, (adding more O2 for the fish too), but my plants have not reached that 'big' stage yet, so I'm not 100% sure on the theroy here!

Hope this helps.

Add comments or your own concerns guys...

 

i know this is probably a lazarus post, but humor me, oh wise ghurus...

Those of you who have built a DIY system, please contribute here your findings and hints/tips that myself and others may learn from it.

Can some of you please post pics of your constructions and how to's or whatever?

(i'm also interested in the pH downing effect, if anyone has some data on that?
mine is at 8-8.2, not a very happy environment for tetra among others, i tried lowering it with peat, but a stocking foot full didn't really dent the pH...)

Can people confirm the effective rate of bpm and such details?

 

The DIY CO2 worked reasonable well. Had to remake the mixture every 3-4 weeks. I'm not too sure how much it effected my pH.

Do a google research on it Ferryman, and give it a try... it'll literally cost you an old 2l coke bottle, 2-3m of tubing, a small thing of yeast (about R5.00) and 2 cups of sugar. (about R10.00). You dont HAVE to go for the bubble counter... because no one here on TASA has been able to actually say how many bubble to add per litre... or how to calculate when you've added too much etc... just put the tubing on an airstone and let it run.

I didn't turn mine off at night, because pH would then go down during the day, and then up at night... not good for fish... so mine ran 24/7. Worked well. (Besides... if you stop the CO2 from going into the tank, it'll cause the bottle to explode overnight.. MESSY MESSY)

 

why would you need 2 to 3 meters of tubing?

-i have two empty 2liter coke bottles (thats how i found this post, forum search "2l and coke"
-i have 1,5 to 2 meters of green rubbery tubing
-i also have sugar abouts, and i have four packets of 10g anchor yeast...

i'm currently just waiting for my canopy to pop into existance, then i'll have a better lighting solution, gathering info in the meantime

 

I did some reading up and perhaps I can contribute a few thoughts.

1. The biggest issue with adding CO2, either pro or DIY, is efficient diffusion. I have experimented with DIY CO2 in a small tank and found that a small powerhead with the tubing attached to the intake is by far the best diffusor. If you want control, you can put the powerhead on a timer. When the powerhead is off, large bubbles will just float to the surface and not diffuse in the water.
2. The other issue with DIY CO2 is inconsistency, which may lead to BBA and other algae forms. I found that by connecting 2 bottles and chaning them out at alternate times provides best results.
3. From what I can gather, and this depends largely on your ph, you need at least 1 bubble per second per 100L of water for a medium planted tank. And this is also related to the efficiency of your diffusion. Less efficient, and you will need to push more bubbles. You can use a CO2 drop checker (google this), and although it is reliable, it has a slow response time and not a fine resolution. You can either have too little, OK or too much CO2. And I don't think those 3 values are a good enough indication.

Regards
L

 

Adding co2 is for plants to get carbon to grow??
Why not just buy Seachem's Excell and dose with the correct amount for your tank.No drop in PH that i could notice and a 1-2cm plantgrowth per 24hour cycle satisfy me.(With trace elements from Seachem as well.)

 

Has anyone tried the Tetra Optimat system with the co2 canister and diffuser? I got one last week and seems to increase plant growth considerably. Any other users out there?

 

i read about it, dunno what it looks like though, if you got yours recently, what did it price for?

how long will a canister like that keep till it needs to be replaced?

 

Its going for R199 at most LFS, dont know how long it will last though. Lfs said about 2 mnths and about R80 for a refill canister. Most LFS dont have many on their shelves so they have to order it for you. This system is very convienient, just fill the diffuser once or twice a day and thats it.

 

aerosol bottle with a bit of airtube on the nozzle, and a little pill bottle sized pipe with very very fine mesh at one end. i googled it.
so co2 goes into the diffuser and slowly releases and dissolves out the mesh end i think

 

I used DIY yeast reactor bottle for about 3 months with no hassle. As long as you maintain a steady input, your pH doesn't get effected too drastically. But keeping it steady also maintains a steady pH. "al cheepo beginner fish" (Angels, guppies, swords, danios etc) aren't too fussy about pH... as long as it is constant! (Discus and other more difficult fish are more fussy.)

I tried a cheap CO2 diffuser method that I bought from lps which basically realses CO2 off of a carbon plate.

thread here

http://www.tropicalaquarium.co.za/showthread.php?p=14806#post14806

It also worked, but in the end was a DISASTER on my filter and substrate. I can't prove that it was this system, but when I rescaped this weekend, I found my substrate covered in black oily mess. I have been cleaning this black oily mess out of my filter every second day too for the last 3 weeks.

I have now gone BACK to the CO2 DIY system. But instead of going with a bubble counter, I have connected the CO2 to my internal filter's ventury system. This also ensures that the CO2 is broken up into smaller bubble and distributed throughout the tank more evenly. The bubble counter apparently looses a lot of CO2 as only 1 bubble released, and according to my research, only 20% of that bubble is released into the water.

I also know that in my tank 1x 2 litre bottle lasts about 4 weeks in my tank. I've downsized to a 1 litre bottle, because that fits nicely under my tank in the cupboard. So I would have to remake my yeast mixture every second maintanance cycle.

 

Zoom, you used a single 2L bottle on a 160L aquarium? And it lasts 4 weeks? How many bubbles per second? What is your mix?

 

At over 100 bucks a bottle, Excel is expensive. Especially if you have tanks over 100l.

Boebie, can you give more info on that Tetra unit? It sounds a lot like the Nutrafin/Hagen unit. Which is basically a DIY yeast unit in any case

 

Not worth it at that price. I'd rather go for the SERA Soda stream kit.

 

No, I'm just saying that at R80 a refill it's fricken expensive compared to other alternatives and you have to manually release the gas everyday, that's just dumb.

 

thats it, its small, noting fancy or mind boggling about it, rather straight forward

Saw a kit like that at a few LFS's on my last visits a week or so ago

 

I'm not putting HECTIC CO2 in. Just a little to assist growth. About 1 drop every 5 seconds... which also gets 'splattered' through the filter pump head making it more effecient. 2l bottle. 2 cups white sugar. 3/4 teaspoon yeast. (Most receipes recomment 1 full teaspoon... I find the more yeast you have in, the faster it reacts with the sugar, so I slowed it down by lessoning the yeast.)