# How long does it take to get the initial co2 into the water?



## OverStocked (May 26, 2007)

how are you defusing it and how many bpm?


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## captain_bu (Oct 20, 2007)

What are using as a "CO2 indicator"? The commercially available tests should not be relied on. If you are using a drop checker properly i.e. filled with 4 dKH water and a couple of drops of bromothymol blue it takes a couple of hours for changes in the CO2 level to register. If you have tank water in the drop checker it doesn't matter how long you wait to check it since the reading will not be accurate. Even a drop checker is not 100% accurate it just helps you get in the ballpark, green means you are close to where you want to be, then you monitor the response of your plants and fish to fine tune levels. Always best to go slow at first with CO2. It is not a good idea to make adjustments to CO2 unless you are going to be home to watch the tank since it is easy to kill your livestock if you add too much. I suggest you wait until a day when you are home to monitor the CO2 levels and response from your fish. Always bump up CO2 slowly and observe the tank every half hour or so. Wait at least several hours between increases. CO2 levels tend to build up over the course of the day so pay particular attention to the tank the last couple of hours of the photoperiod. If your fish seem lethargic or are clustered at the surface trying to get oxygen you need to lower your CO2 levels.


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## EricSilver (Feb 23, 2004)

Tracy said:


> I have a 55 with 1 power filter and 1 biowheel filter - so I have a lot of movement on top of water. (This is an expensive hobby - the canister filter is next).


How does your water enter the tank? Are the outlets above or below the water surface? 

I ask because I have an Eclipse 3 hood with biowheel and extended my outlets below the water surface, which is now as flat as glass with no rippling. (I posted the simple mods in the “Equipment” forum last year.) This had the added effect of slowing the biowheel, which does not cause any significant CO2 out gassing. 

The only turbulent water surface in my tank is where the filter intake pumps water onto the filter pad. But because this surface area is so small, approx 3 inches by 9 inches, CO2 out gassing is significantly minimized. 

In my 29G It takes about 45 seconds for variations in CO2 output to be felt by plants (evidenced by increases/decreases in O2 bubble rates from snipped leaves). So, for a biowheel system, my tank is quite airtight. If you have the ability to extend your inlets below the water surface, you might want to consider doing that before buying a canister.


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## Tracy (Apr 2, 2009)

Thanks for the pointer about the bio wheel. 

When I got home from work I turned it on pretty high. Stupid question: how do I know bpm? too fast to count. It took 2.5 hours for the indicator (cheap little plastic thing suction cupped to inside of tank with tank water in it) to turn green. I just shut it off. So tomorrow maybe I'll turn it on slower and see how long it takes. My diffuser is a small plastic container with an airstone type lid on it so very small bubbles come out - very high tech. jk.


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## EricSilver (Feb 23, 2004)

If it’s too fast to count then you are running rather high, and probably not at a safely sustainable level. I suspect you may have a leak if you are using that much and your in-tank level is not rising. When I first set up my CO2 the bubble count was a blur, with moderate outflow from wood airstones, until I discovered a leak at the bubble counter. 

Do you have plants? Pick a fast-growing stem plant, or a grassy one like dwarf sag, snip the top of a leaf or blade, and watch for oxygen bubbles out of the snipped leaf. To raise CO2 very quickly (in about a minute) here’s what I do: Open the needle valve wide, “boiling” the water. In my tank, 1bps of O2 from a cut leaf tells me that CO2 saturation is more than adequate, at which point I turn down the CO2 until the 1bps O2 rate (or a slightly lower rate) is sustained. I then note the bubble count and that becomes my reference. (The drop checkers and other indicators are useful, but I prefer to let the plants tell me when they are getting adequate CO2.)

If you do this, pay close attention to the fish. If you start to overdose, they will begin gravitating towards the surface. (But you are not at risk until they start gasping at the surface.) Ottos and cories may shoot up for a gulp of air. If that happens, reduce the CO2, but fish are very unlikely to react before the plants do.

2.5 hours seems a long time. I’ll assume your indicator is working and will again suggest looking for leaks in your airline. Below is a photo of mine when it was first set up. The horizontal blue tube is where my leak occurred, by opening a tiny gap in the cap of the bubble counter. Based on my before and after bubble counts, more CO2 was escaping the counter than entering the tank. There was no hissing or other indication of it. Once that tube was straightened out, the gap closed and instead of a bubble blur, my current rate of 2-3bps produced the same airstone output as before. 

Coralife wood airstones also produce an ultra-fine mist and are what I use. If for some reason you become dissatisfied with your diffuser, they are an excellent alternative.


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## EricSilver (Feb 23, 2004)

Correction: 2.5 hours is not a long time. Your tank is about twice as large as mine, so you should be be OK. So check for leaks as part of general maintenance, but not as a potential problem.


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## Left C (Nov 15, 2003)

Tracy said:


> ... Stupid question: how do I know bpm? too fast to count. It took 2.5 hours for the indicator (cheap little plastic thing suction cupped to inside of tank *with tank water in it*) to turn green. ...


You should be using a lab certified 4dKH solution in your drop check along with the pH indicator solution.

The directions may say to use *aquarium water*, but that is *wrong*. You should be using the solutions that I mentioned above.

There is a ton of info around about using a known 4 dKH with the pH indicator fluid telling how it works.

Try this and then adjust things as needed.


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## Tracy (Apr 2, 2009)

thanks for all the info! I think I meant bps, right? Not bpm. Anyway, I turned it on this morning very low - 1 bps. I am going to see where the indicator is after 2.5 hours. I'll check for leaks, Try to do that oxegen test with a plant, and I'll see about getting some of that 4dkh solution. I noticed last night when I shut it off that the guppies were hanging at the surface. The angelfish, neons, and corys weren't though. Everyone was still alive this morning.


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## EricSilver (Feb 23, 2004)

Tracy said:


> I noticed last night when I shut it off that the guppies were hanging at the surface. The angelfish, neons, and corys weren't though. Everyone was still alive this morning.


I have learned that Amazon fish are the most tolerant of low PH, I suppose because the Amazon river is rather acidic. When I would turn up my CO2 too high, my Tiger Barbs would be gasping at the surface while my Tetras were meandering about on the bottom, as if nothing was wrong. Come to think of it, my Ottos spend a great deal of time near the airstone, directly in the CO2 mist. 

Based on the behavior of your fish, you are close to your optimal BPS rate. If you recall what you had it at last night, crank it down a bit until the guppies start acting normal, and leave it at that level. Then do the plant snip test.


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## Tracy (Apr 2, 2009)

I found a great chart in a book. You measure The KH and the PH and it gives you an estimated ppm. I haven't had a day off yet - tomorrow will be my first day to try to figure this out. thanks for all your suggestions. I am learning a lot.

Tracy


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## Homer_Simpson (May 10, 2007)

Tracy said:


> *I found a great chart in a book. You measure The KH and the PH and it gives you an estimated ppm*. I haven't had a day off yet - tomorrow will be my first day to try to figure this out. thanks for all your suggestions. I am learning a lot.
> 
> Tracy


Oh...you mean like this on-line chart?
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

Sorry, to be the bearer of some bad news, but the chart method is not deemed to be as accurate as drop checker since your tank's PH and even KH could be effected by many factors that would easily give you a inaccurate reading. Do yourself a favor and get a drop checker with an appropriate 4dKH solution.

You can even make your own 4dKH solution.
http://www.plantedtank.net/forums/general-planted-tank-discussion/42429-kh-standard-how.html


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## Tracy (Apr 2, 2009)

problem: I have the light set to go off for 2-3 hours in the middle of the day (my attempt at keeping toxic algea explosion at bay). I've noticed that if it's running at about 2 bps, it doesn't start up again when everything comes back on. It's not that the gas is still off, because there's still some bubbles, maybe 1 every 3 seconds. It will only start up again if it's running real high - too fast to count. Could there be a leak? I'm going to try to post pics of what I got.


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## Tracy (Apr 2, 2009)




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## EricSilver (Feb 23, 2004)

Tracy said:


> problem: I have the light set to go off for 2-3 hours in the middle of the day (my attempt at keeping toxic algea explosion at bay). I've noticed that if it's running at about 2 bps, it doesn't start up again when everything comes back on. It's not that the gas is still off, because there's still some bubbles, maybe 1 every 3 seconds. It will only start up again if it's running real high - too fast to count. Could there be a leak? I'm going to try to post pics of what I got.


Turn lights off, but leave CO2 on?


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## Tracy (Apr 2, 2009)

I thought it needed to be off when the lights are off?


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## Tracy (Apr 2, 2009)

http://www.ukaps.org/drop-checker.htm

This helps.


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## EricSilver (Feb 23, 2004)

Tracy said:


> I thought it needed to be off when the lights are off?


Not necessarily. Mine runs non-stop. And you are talking about only a 2-3 hour period.

When you turn your lights off, during the middle of the day, the plants don't stop photosynthesis; they simply look for another light source. 

When my plants do actually "go to sleep," and switch from photosynthesis to respiration, they will fold their leaves. They follow a natural rhythm/cycle that is impossible to alter by varying lighting. At about 8:00 a.m. their leaves begin opening, and at about 9:00 p.m. they begin closing, regardless of my lighting cycle. (If I keep lights on after about 9:00, algae growth accelerates.) 

Another example: When I go away for weekend I shut my tank lights off. When I return, the stem plants have reoriented themselves towards my balcony windows, where some light trickles through. After the tank lights are back on, they straighten themselves out. The fact that the tank was dark for 2 or 3 days did not interrupt their natural wake/sleep cycle. As long as there is even a faint light source, their sensors will detect it and move towards it. (I would imagine only pitch darkness would cause them to go dormant.) 

So, even though your lights are off for a couple of hours, the plants are still photosynthesizing and still need CO2.

EDIT: The rate of photosynthesis will slow, but not stop, when the lights go out.


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## EricSilver (Feb 23, 2004)

Tracy said:


> http://www.ukaps.org/drop-checker.htm
> 
> This helps.


Yes -- and Planted Tank's sponsor, Green Leaf Aquariums, is outstanding and I'd recommend having a look at them:

http://www.greenleafaquariums.com/co2-drop-checkers.html
http://www.greenleafaquariums.com/


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## captain_bu (Oct 20, 2007)

Tracy said:


> problem: I have the light set to go off for 2-3 hours in the middle of the day (my attempt at keeping toxic algea explosion at bay). I've noticed that if it's running at about 2 bps, it doesn't start up again when everything comes back on. It's not that the gas is still off, because there's still some bubbles, maybe 1 every 3 seconds. It will only start up again if it's running real high - too fast to count. Could there be a leak? I'm going to try to post pics of what I got.


It sounds like there is something wrong with your CO2 rig, may be a low quality or flakey needle valve. Also not sure you are gaining anything by interrupting your photoperiod. I have never tested myself but have read that breaking the photoperiod may instead benefit algae since algae is opportunistic and much quicker to respond to light, CO2 (or nutrients that are not in balance) than plants are, the plants take a bit of time to "get up to speed" on photosynthesis after the lights come on. Try to stick with a continuous 8 hour photoperiod. I run my lights from 2:30—10:30 so that they are on more of the hours that I am available to look at the tank.


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## Tracy (Apr 2, 2009)

captain_bu said:


> It sounds like there is something wrong with your CO2 rig, may be a low quality or flakey needle valve. Also not sure you are gaining anything by interrupting your photoperiod. I have never tested myself but have read that breaking the photoperiod may instead benefit algae since algae is opportunistic and much quicker to respond to light, CO2 (or nutrients that are not in balance) than plants are, the plants take a bit of time to "get up to speed" on photosynthesis after the lights come on. Try to stick with a continuous 8 hour photoperiod. I run my lights from 2:30—10:30 so that they are on more of the hours that I am available to look at the tank.


I have read and heard the opposite - plants start photosynthesizing emmidiately and algae needs time. This is one of the frustrating parts about this hobby, there's a lot of conflicting information.

Now that I have co2 I'm not breaking up the daylight hours. I just did that because I had to go to work and wasn't going to be there to moniter co2 level. I am starting to figure this out. Not an exact science is it?


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## EricSilver (Feb 23, 2004)

Tracy said:


> . Not an exact science is it?




That's what makes it fun.


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## Tracy (Apr 2, 2009)

Yes. and obsessive. :fish:


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