# DIY CO2 out of control, high levels - too high?



## CatG (Apr 10, 2010)

It seems I am having nothing but problems with my tank (my first). I am beginning to become very discouraged.

When I first set up my tank, I added 3- 2 liter DIY co2 bottles, which steadily produced 31ppm until the mixture expired. I have since swapped out two of the bottles, with plans to swap out the third today as their mixtures were due to expire. I used different yeast this time, and my co2 has gone from the stable 31ppm with the old mixture to 97ppm today (was 55 yesterday following the changing of the first bottle, went to 97 following the change of the second bottle), and this is with the 3rd bottle unchanged. Yesterday, I added 4 albino corys to my tank (the only fish in there), and I am worried the CO2 increase an PH drop will kill them.

My tank is a 75 gallon long. My PH is currently at 6, my CO2 is 97ppm, the tank is moderately planted, and I fertilize with Flourish, Flourish Excell, magnesium sulphate, potassium nitrate, and potassium phosphate. ~2wpg with 4x40 watt T12s. What should I cahnge to fix this if these levels are a problem? Should I go down to 2 bottles of CO2 instead of 3? Should I leave off some or all of the ferts (don't know if those have any effect)?

Thanks,
Cat


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## Seattle_Aquarist (Mar 7, 2008)

Hi CatG,

I only changed one bottle at a time and tried to always use the same yeast and mixture. 

I have had this happen in the past. I disconnected my CO2 and added an airstone to increase surface agitation and water circulation which will help lower your CO2 level. Continue your ferts and reconnect your CO2 when the level is back to normal and when you have some a several of hours to monitor the CO2 to make sure it doesn't go too high.


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## Big_Fish (Mar 10, 2010)

OWCH... Hi, CatG... 
WOW.. that's a LOT of co2.. I'd disconnect one of those bottles. Maybe use it to get your next batch mixed and started.
I've got albino cory's in my 29 gal, THEY WILL NORMALLY dart to the surface and gulp air occasionally. this is normal behavior for them and is not necessarily a sign of O2 starvation.

That being said, 97PPM is incredibly high... are you confident that your PH is actually 6.0? 
you should be seeing roughly 3 times the bubble count that you had with the last 'stable' batch.. if that's the case, definitely ditch one of the bottles. (My 29 gal does roughly 45 bubbles in 30 secs... 1.5 BPS. and that gets about 25 PPM co2 in that tank... you must be getting close to a continuous stream of co2. )

the low PH shouldn't harm anything, but the high C02 levels may... keep an eye on the fish... should you find them remaining at the surface and gulping for air (particularly in the morning before the lights come on) that's a definite warning sign: too much Co2, the only way to fix that one is to not pump so much in.

I hope this helps.


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## CatG (Apr 10, 2010)

Thanks for the replies!

Yes, I WAS getting a constant stream of CO2. No little individual bubble noises, just a constant noise. I have unhooked one of the bottles, and still it's just shy of being a constant stream, but I can now hear individual bubbles going up. Don't know how many, but I would guess at least 3 per second and maybe a tiny bit more.

I think it's the yeast. I don't think they had the kind I got at first, so I bought what they did have. I need to see if I can get some of the original stuff again, as I think this stuff would surely burn itself out fast if it's producing this quickly and this much. I will do what I can to get the CO2 back to normal, even if I have to go down to one bottle. If this stuff lasts more than 9 days though (the length of time the original stuff lasted), I will keep using this new yeast and just use less bottles.

Another thing I noticed is that tiny bubbles are collecting just under the surface of the water. I have a bit of an oil slick going on, so I need to get rid of that I think. It may be keeping some CO2 in, keeping the levels elevated. I've tried the paper towel method of removal, but there's got to be a better way. I wonder if I stuffed some paper towels in some pantyhose and anchored it somewhere where the water will flow through it, if that would work in keeping the oil under control. I don't know how long the paper towels would last though before they started to fall apart. Maybe I will experiment with some oil absorbing stuff and see if I can't come up with a replaceable filter that I can leave in the tank. It may be a bit unsightly, but it would be great if I could make something work.

Thanks for the help guys!
Cat


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## Big_Fish (Mar 10, 2010)

a little surface agitation should keep the 'oil slick' in check. 
the filter outflow can be used, an airstone/bubbler. the trick of course is to get enough surface agitation to break up the oily film, but not so much that the gas exchange is so great all the co2 gasses out.


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## James He (Aug 24, 2009)

Are you sure you get the reading right? it was impressive by using DIY CO2 bottles to get that high reading.

I think it would be cheaper if use CO2 tank.because you can use a timer to stop inject CO2 during night, it can last few months before refill the tank.

I only change my DIY bottle once a week to keep it cheap.


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## mats808 (May 7, 2008)

Hi Cat,

You didn't mention if you are using a filter but if you are another thing that you could do is make some kind of a makeshift overflow box for the filter intake. This should just about eliminate the "slick". Granted all that "stuff" will just be transferred into the filter but at least it won't be covering the surface of your water.

Big_Fish's suggestion of the airstone should also help manage the slick. The agitated water surface will also help some of the CO2 escape.

It sounds like your old recipe (yeast) worked perfectly. You should go back to that as soon as possible but as a quick fix you could change where you are releasing the CO2. Try putting it in a position that minimizes the time each bubble is in contact with the water. In other words try to do the exact opposite of a CO2 reactor.

I hope this helps. Good luck.


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## CatG (Apr 10, 2010)

Yes, I am using a filter, and have redirected the output so it agitates the surface a little more. I am also running a powerhead. The oil seems to have dispersed for now, but I will keep an eye on it.

And I am also fairly sure the test was right. If the CO2 had not been coming out in a constant stream, I would have doubted the results, but it was shooting out of there pretty good. (The co2 tube goes directly into the filter intake tube, and you could see the stream going up in the tube.) I unhooked one of the bottles a couple of hours ago, and things have now settled back to normal. My latest test showed the PH is back up to 6.5, and the CO2 is back to 31ppm. If this holds steady for the life of the mixture (should be about another week), then I will continue to use this yeast and stay with 2 bottles instead of 3.

What worries me though is how steady the production will remain. I have a feeling I am going to be battling this constantly, and will have to keep a constant eye on it. When I first unhooked the 3rd bottle, I was getting about 3+ bubbles a second. Now, after a couple of hours, it's back to about 2. Who knows what it will be in another couple of hours.

I can't get a CO2 canister/regulator/needle valve for a good while, so this will have to suffice. Is there any sort of receptacle I can get/make to house the co2 that's being produced, and have it's release into the tank regulated from there? You would think there'd be a way to do it, since the DIY bottles essentially take the place of a pressurized canister, but I would be worried about the lack of a safety valve on the DIY bottles. If I could find brass fittings that fit the bottles, maybe I could add a regulator and safety valve on to that, then a needle valve to control the release. Doubt I could find fitting that would work though, although it's possible I could have them fabricated. I will have to look into it.

Thanks again guys for helping me out of yet another situation!
Cat


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## Seattle_Aquarist (Mar 7, 2008)

CatG said:


> I can't get a CO2 canister/regulator/needle valve for a good while, so this will have to suffice.


Hi CatG,

Watch Craigslist For Sale for CO2 cannister / regulator, if there is Craigslist in your area. I type in CO2 for the Search. In Seattle there are usually several posts per week; usually someone getting rid of old beer equipment. I picked up a 20# aluminum CO2 cylinder and regulator for $35 and they looked brand new! I added a needle valve and I was done.


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## CatG (Apr 10, 2010)

Just a quick update on this - I noticed that I had used "highly active yeast" during my problem period, so I went to the store and bought some that was simply titled "active yeast", which is what I had used in the beginning. I wouldn't have guessed there was any difference, but once I switched back to the "active yeast" and got rid of the "highly active yeast", things calmed down and stabilized.

Is there a difference between the two, or was it possibly simply a difference in brands? I'm guessing there is a difference, as the "active yeast" I used in the beginning was a different brand than the "active yeast" I am using now, but I am gettig the same results from both - CO2 stable at 31ppm. With the "highly active yeast", I got up to 97ppm.

Cat


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## Big_Fish (Mar 10, 2010)

Highly active yeast produces more C02 than regular active dry yeast... 

Brewers yeast is able to survive and thrive in higher alcohol content than bakers yeast also.

There are literally thousands of different strains of yeast, each with their own properties.

http://answers.yahoo.com/question/index?qid=20090328073328AArAmVx


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## CatG (Apr 10, 2010)

LOL now I know.  The regular yeast works good, so I am going to stick with that. Now the only problem I am having is keeping the lids from leaking. It's a crap shoot every time I have to change out the bottles. Things will be going along fine, then I go and open the bottle up for a mixture change, and when I put the lid back on, the lid leaks. Once in a while the change out goes ok, but more often than not, I end up with a leaky lid that had been working fine until I opened it.  I try to be real careful with it when I open it, but they're just too delicate.

If I can just make it until Christmas, I am going to ask for a nice CO2 setup. I really like the ones with the PH monitors on them. One thing I don't like about the CO2 setups is the huge reactors. I really don't want that big thing in my tank. I'm hoping I can skip the reactor and just run the tube directly into my filter intake like I have it now.

Anyway, thanks for the help!
Cat


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