CO2

[Maxy]

Would someone please be kind enough to explain what co2 does for plants in a tank. I know they need it to survive, but how does it work and should I be using it to grow plants? My plants are adequate, but nothing like the flourishing lush looking members tanks! Thanks

[Modern Angl]

plants take in CO2 to grow by absorbing the carbon and expelling the excess oxygen. If you add in higher levels of CO2 into your tank, the plants have more carbon to absorb and their growth basically triples overnight.

Your plants will grow without adding CO2, they will grow *really* fast with a good CO2 supply going into your tank.

[PENEJANE]

hmmm guess thats something I need to look into also. I have also been told that at night when the lights go out that the plants sleep and during this time (untill first light again) the plants acutaly asorb oxygen and release Co2. I could be totaly wrong but thats what I was told or read somewhere.

How is Co2 set up and how expensive is it? Is there other alternitives that would do similar things to plants?

[steve slack]

you can set up a basic co2 unit using the yeast method

do a search on google for more info

[Luke*]

Aside from light, carbon dioxide is the most important nutrient for plants. There's lots of info about DIY CO2 and pressurised for that matter. Lots of people still have success with ferts and good light. Some CO2 is produced from the fish and absorbed in to the water from the atmosphere. For real lush growth though you want CO2.

[HummingBird]

hmmm guess thats something I need to look into also. I have also been told that at night when the lights go out that the plants sleep and during this time (untill first light again) the plants acutaly asorb oxygen and release Co2. I could be totaly wrong but thats what I was told or read somewhere.

That's true, but they absorb so little oxygen at night it doesn't really matter.

[PENEJANE]

I was just looking up a DIY Co2 yeast setup and as I was talking to my husband about it he said wouldn't it cause more harm to the fish? How can I be sure that I don't have a bad balance of Co2 and Oxygen to harm the fish?? I don't want to put Co2 in there and have it over run the oxygen balance and kill my fish. Expecially while I got babies (had them this morning )

How can I be sure that using this setup won't do more harm than good. I have been adding new plants every couple of weeks due to others dying off so I want to fix this problem also but being a newbie to all this is really confusing at the same time.

Cheers

[freshwest]

From what i understand co2 will not displace o2 in your water .

To have lush growth in a planted tank you need in basic terms

Light + Balanced Nutrients + CO2 . If one or another is in short supply you do not get maximum growth.

[PENEJANE]

so if I was to do the DIY Co2 yeast method once a month (artical I read says it will last from 10-14 days before needing to be replaced) would that be enough??

So basicly there is no way I can kill my guppies by adding Co2 to the tank?

[misnoma]

well if you put the cylinder in the tank and batted the guppies around with it they might die

For the $30ish on trademe, I would get a Hagen CO2 toy as opposed to DIY, purely because it saves messing around, refills are pretty cheap on there as well and seem to last a good month (I'm running one of these in each of my tanks and the plants are loving it). Just watch for the expiry date on the refills being sold on trademe....

[DiverJohn]

Hi Pene

CO2 is a tricky wee beastie. And I suspect that the best thing do say is that "yes CO2 could harm your fish" but as in most things there is a but, several infact.

On its own, uncontrolled addition of CO2 to pure water will lower the pH (7-) due to the formation of (and correct me someone if i am wrong) carboxylic acid. A particularly low pH is undesirable in most aquariums - but that depends on what yo are doing - my community tank is between 6.6 & 7 with the CO2 running.

This can be corrected with the addition of buffers to increase hardness, but this should be done in moderation as too much buffer can cause the ph to rise (7+ )

And there is more to it than that....

BUT (theres that word again!) when i started trying to get my plants to grow better i used yeast CO2. results were good. So perhaps you could try this... its what i did...

Add your CO2, keep your air pump working, note the ph. test your ph regularly over the next day or so if everything looks ok, try putting your airpump on a timer and turn it off during the day for 6 hours. It would be a good idea to test ph morning and night. if it starts dipping too low, turn the air pump on for longer. If it looks OK, turn the airpump off for longer until the airpump is off all day and on at night.

Anyway hope that helps, i just kept an eye on things and took it slowly, then you get annoyed with yeast!!

[PENEJANE]

I was just looking into it as a once a month boost for my plants. Most of the articles I have been reading today state that the yeast method last from 10-14 days and some up to 3 weeks. I am not really interested in running Co2 24/7 at present but just wanting to give my plants once a month if not once every two months in case they are not getting enough from the tank as it is. My plants are all cuttings so none of them have actually established yet (maybe 1-2 have good rooting system on them). So basicly I am just wanting to give them a booster like a vitamin C tablet does to us humans

BTW my husband is a plumber so I can get him to make up my Co2 container easily

(at least hes good for something hahahah)

[DiverJohn]

If your using that kind of anaolgy then I think it woud be fair to say that to a plant, CO2 is like "Air" to us humans.

[PENEJANE]

lol yeah

At present I don't have anything to difuse the Co2. But I am able to hook it up to 1 or 2 small ceramic, fine bubble airstones. Would it be better to use both (one at each end of the tank) or just the one at one end of the tank??

Thanks a heap for your info so far on this.

[Maxy]

Im in the same boat Penejane as my plants are still establishing. I use Excel Flourish once a day and that helps, but want to know if running CO2 would work out cheaper. I want healthy plant growth especially tall plants to hide my equipment but wonder if just using fertiliser would suffice? Also do I need a stronger light as I'm currently running a single 30watt in a three foot 180 litre tank

[PENEJANE]

Wow maxy you got a large tank! My tank is only 90ltrs. As of tonight I am trying a yeast Co2 system to see how it goes for a week. I should take a before and after picture of the tank I guess to show a difference in plant growth (if it works).

BTW maxy what fish do you have in your tank?? I am looking at selling/trading some baby guppies in a couple of months. I don't think that east rd will accecpt my babies even if they were to be free and I don't want to cull them just because of over stock.

[Maxy]

Hope the co2 goes well. If it does I may have to comission your talented husband to build me one! I have a community tank with guppies in it and am waiting for my first drop of fry, but dont expect many to survive as I have some fish that will probably eat them! But if you have some established fry that you want rid of later on then I might be able to take some. Talk to east road tho as you might be able to give some to them.

[PENEJANE]

Well I think my Co2 is going to work which is a big but its still early days yet. All I done was get a 2ltr soda bottle, drilled a hole in the top to the size of the air tubing (husband done that part hehe). Inserted the tube and put a good blob of plumbers putty (like blue tac but extra sticky) and put a 15x25mm airstone on the end and droped it in the tank. Gave the bottle a bit of a shake up to start the flow and bobs ya uncle

The plumbers putty isn't working to well as a proper seal so I am going to try some hot glue tomorrow (hot glue gun) and see how that seals it. If that don't work then I will nick some of the hubbies silicon as that should do the job and create a good seal.

The yeast method I used (from net) is 2 cups sugar, 1/2 teaspoon yeast and about a 1.5 ltrs of warm water (to activate the yeast).

I took some pictures last night of my tank and will take another one at the end of the week and see what results I have (if any)

Fingers crossed

[Warren]

Well I think my Co2 is going to work which is a big but its still early days yet. All I done was get a 2ltr soda bottle, drilled a hole in the top to the size of the air tubing (husband done that part hehe).

Next time, make the hole one drill size smaller than the tubing and force it into the hole. No need for glue as it will seal itself.

Keep an eye on the fish when you start to add CO2. If they start looking distressed and are breathing at the surface there is too much CO2 for the amount of light. You often have to increase the amount of light when adding CO2...

[Shilo]

Did the DIY CO2 thing for a year until I decided to go low maintenance. You can get very good results. Almost had to borrow a weed eater every week so I could clear the tank enough to find the fish :lol:

BUT like man can't live on vitamin C alone, your plants will need more then just CO2. Adding CO2 will make very little difference in plant growth unless they can process it. To do this they need light, nutrients and more light. The more CO2 they get the more light and nutrients they will need. If one or the other is missing then they will slow down growth until a natural balance is reached.

For an example, my tank is 185 ltr (160 tank/ 25 sump). In low maintenance mode it has 72 watts of flouresent lighing, no ferts and no CO2 (reasonably highly stocked with fish). Plant growth was Ok but I only had to prune once every couple of months. In high maintenance mode it was running 122 watts of lighting, 2x 1.5ltr bottles of CO2 bubbling away (completely dissolved) and I added 15ml of "Yates Lush" a week. Pruning was a weekly affair with the Anubias nana flowering, and the other plants streaming out O2 air bubbles.

In both these examples everything was in balance so I had no problems. Unfortunetly finding these balances is THE hard bit! If one thing is missing then not only will plant growth even out but Algae will take advantage of the situation and be very happy using the left over parts of the formula. Secret is to increase things slowly so plant growth can keep up with the changes and starve out the algae.

Light + CO2 + Fertilisers = Growth

Light + Fertilisers = Algae :evil:

Light + CO2 = Algae :evil:

Fertilisers + CO2 = Algae :evil:

etc......

[PENEJANE]

well I got a fluro light which is in the hood above the tank. The Co2 has stoped working as I think I didn't mix it up properly (water not warm enough to fully activate the yeast) but I will keep trying with it and look into getting another bottle and make the hole smaller.

My tank isn't completly sealed as it has holes to allow for the cords and the bubbles are going straight to the surface but the bubbles were comming out really slowly so I thought that even tho most were just dissapearing that there would still be a small amount getting into the water. I don't use Fertalisers in my tank as its just a bit to much $$ at present and the only reason for why I tried the Co2 is because there was a home DIY version. Otherwise I wouldn't of bothered.

But I will keep going this way (but seal it better) and see how it goes for a week. Everything is always trial and error just hope there isn't to much errors :oops:

[Shilo]

Don't get me wrong, you are going the right way to become a plant addict

Not having a close fitting lid shouldn't matter. I use a wet / dry trickle filter which nearly everybody says is a no no for CO2 ( a W/D filter exposes a lot of the water to air which allows the disolved CO2 to escape).

To get the max out of the CO2 you want it to disolve in the water. To do this a bell (upside down container under the water level) with a large surface area could be used or very fine bubbles (airstones are too large and will quickly clog). An alternative if you have a canister filter is to feed the CO2 line into the filter (via the intake pipe?) so it gets churned up and mixed with the water.

Put your CO2 bottle on top of the tank near the light. There should be enough heat here to keep it going. The mix you are using is the same as what I used. Adding 1/2 a teaspoon of baking soda will keep the PH down and let the yeast live for a bit longer. Tried brewers yeast and another type I scored from a local winery. Didn't find any difference in the length of time compared to normal bakers yeast. Used to alternate refreshing the mix once every 2 weeks. The yeast lasted about 3 weeks.

I used hot glue on both sides of the lid to seal around the tube. Found that forcing the tube still leaked a bit if the tube was bent over and silicon only lasts a day before the CO2 reacted with it and it lets go.

Only 4 bad things could happen: Algae growth, leakage into the tank (overfull bottle or drastic yeast production), major PH swings, or tank water syphoning into the bottle if bottle is below water level. Apart from the PH swing nothing else will harm the fish.

[PENEJANE]

Thanks for all that info I shall do a pH test in a few mins. Just want to finish breakfast to warm my tum tum up

[suphew]

I would suggest that you don't run the CO2 for only a few days (or couple of weeks) a month, but leave it going.

The CO2 will change the PH, this isn't a bad thing (can be a good thing depending on the type of fish) as long as it isn't exstream, which it is unlikely to be using the yeast method. But if you make the PH swing by adding then removing the CO2 often this is a bad thing, the key to fish keeping is stability, fish will happily adjust to different conditions but don't like constantly changing conditions.

Few things to watch when using the yeast method,

1) if you keep the yeast bottle below the tank level it is possible it will start to syphon the tank when the yeast runs out so keep it on top of the tank, on the light is a really good place cause the heat during the day make the yeast work harder while the light are on, which is when you want it.

2) some time the yeast goes crazy and you can end up with the yeast mixture filling the bottle and going into the tank, there are plans somewhere here to add another bottle to the system to prevent this, basically the CO2 goes out of the main bottle, then into a second empty bottle, feeds out of here to the tank.

3) there can be a surprising amount of pressure generated by the yeast, I have read a few stories about people getting a blockage in there feed tube and the bottle exploding, spraying yeast mixture everywhere. So only use plastic bottles (not glass) and do as Warren (?) suggested and just push the feed tube so it can come out if the pressure gets to great. Please dont get worried about this, it isn't common and is just messy not dangerous.

4) it can take a couple of days for the mixture to start working, so to limit the swing in PH you should start a new bottle going before the old one runs out and swap them before they stop.

[PENEJANE]

thanks a heap for that great info I did a pH test this morning and it hasn't changed (touch wood) my tank usually sits at 7.0pH and max it has gotten is 7.5pH so hopefully it won't affect the fish too dramaticly.