# I am pretty sure co2 is killing my fish



## Subaru4wd (May 6, 2011)

I started injecting CO2 with a DIY kit i made using a 2liter and 1gal bottle combined.

Since then my catfish jumped out of the tank. He's now medicating in a seperate tank. And since then both my Angelfish seem to be slowly dying. One of them I found today at the bottom of the tank, laying there... still breathing but definatly dying. The other Angelfish has not come off the surface of the water in two days... it appears he is trying to breath air... not water. And he has not been eating.

My PH has definatly been effected by the Co2. Last tested my PH was at 6.2 where its normally in the 7.0 range.

What are some things I can do, other than removing CO2 all together?


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## majerah1 (Oct 29, 2010)

Do you have a drop checker?Have you seen the fish at the top gasping for air?Have you been leaving it go night and day?Its best to shut it off during the night.A DIY can be done by popping off a piece of the tubing.Just plug it back up in the morning.
'
I dont think unless the PH dropped rapidly,that that would effect the fish.How are you diffusing it?


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## Subaru4wd (May 6, 2011)

Yeah the angelfish (both) hadn't left the surface of the water and i do notice my gourami staying closer to the top of the tank. And now that I look at it, 2 of my 3 tetra are at the top of the tank as well.

I dont have a drop checker, and yeah i leave it run day & night. I didnt know I should have it in cycles. I have disconnected the bottles, but i hate the idea of letting all this CO2 go to waste. Better than all my fish dying I suppose 

I am difusing it by using a air stone that is about 4" long. its making some pretty fine bubbles that travel 30" from the bottom of the tank up... where it gets blown around by the exhaust from my canister filter.


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## majerah1 (Oct 29, 2010)

yeah gas it out with the airstone.The fish should be fine if you get it pretty fast.

Plants use the CO2 all day,but use oxygen at night.I did leave mine going as well, but depending on the mix,if its too strong,then it will add too much CO2 and the fish wont be able to handle that.Whats more,the plants actually use oxygen at night.So this also takes it out of the water.


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## James0816 (Jun 19, 2009)

You're injecting CO2 via DIY with both a 2L and 1g bottle? How big is your tank? Is this the 88g in your signature? If so, I will guarantee that the CO2 is not your issue.


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## Subaru4wd (May 6, 2011)

James0816 said:


> You're injecting CO2 via DIY with both a 2L and 1g bottle? How big is your tank? Is this the 88g in your signature? If so, I will guarantee that the CO2 is not your issue.


Yeah its the 88gal.


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## jrman83 (Jul 9, 2010)

James0816 said:


> You're injecting CO2 via DIY with both a 2L and 1g bottle? How big is your tank? Is this the 88g in your signature? If so, I will guarantee that the CO2 is not your issue.


I would say the same. I look at the amount of CO2 that comes out in my 75g and it is probably 3 bubbles per second.....but it is only on for about 7hrs. Do you know how many bubbles you are producing in a minute?

If you wanted to rule the chance out, just set up a bubbler to come on when your light goes out. It will gas out the CO2 when it really isn't needed.


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## Subaru4wd (May 6, 2011)

jrman83 said:


> I would say the same. I look at the amount of CO2 that comes out in my 75g and it is probably 3 bubbles per second.....but it is only on for about 7hrs. Do you know how many bubbles you are producing in a minute?
> 
> If you wanted to rule the chance out, just set up a bubbler to come on when your light goes out. It will gas out the CO2 when it really isn't needed.


i have ALOT of co2 comming out. Its a constant stream out of this 4" airstone. I have a small mayonaise jar that both the 2 liter & 1 gal T into, and that is my pre-filter.... i constantly see bubbles going into that jar. If I had to count, i'd say 90 to 100 bubbles a minute. 

When I disconnected the tube leading from the filter to the tank this morning (to disable the CO2) that mayonaise jar and both 2liter & 1gallon released all the pressure. It was quite a bit of pressure built up in all 3 containers. Now that there is no backpressure on the filter... i am watching it produce even more bubbles. quicker.


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## Subaru4wd (May 6, 2011)

Oh and I just performed an Ammonia test on the tank, and it came back 0.25ppm

I also did a PH test, and I couldnt determine the results. It appears it maybe lower than 6.0, as thats as low as my test will go. I performed two tests, and neither my wife nor I could figure out the results. So Im going to say its under 6.0... which is a drop from Monday when I tested it at 6.2

I tested my 36gal and its always been at 7.0-7.2 The water out of my tap comes at 7.4.


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## jrman83 (Jul 9, 2010)

So maybe 2 bubbles per second then....that definitely shouldn't cause an issue. Even if you hit 3, same. Your system isn't under any real pressure like most systems, so your CO2 bubbles are not as concentrated as a pressurized system. For example, I operate most of my systems at 35psi. This higher pressure as compared to near zero pressure, forces a much higher concentration of CO2 in the bubble. The bubbles are actually larger also.

Like I said, get the bubbler to play it safe.


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## Subaru4wd (May 6, 2011)

Well what can I do to help the fish out? I want to try to keep my PH as close to 7 as possible.


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## beaslbob (May 29, 2009)

Subaru4wd said:


> I started injecting CO2 with a DIY kit i made using a 2liter and 1gal bottle combined.
> 
> Since then my catfish jumped out of the tank. He's now medicating in a seperate tank. And since then both my Angelfish seem to be slowly dying. One of them I found today at the bottom of the tank, laying there... still breathing but definatly dying. The other Angelfish has not come off the surface of the water in two days... it appears he is trying to breath air... not water. And he has not been eating.
> 
> ...


Sounds like removing the co2 would be the first thing to do.
You're definately increasing co2 by large amounts with that pH drop.
In my planted tank I have a pH of 8.4-8.8 (api high range test kit) Because the plants are consuming the co2.

my .02


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## jrman83 (Jul 9, 2010)

You need some type of surface agitation and you can disconnect it at night....if you didn't want to add a bubble bar or something. You should get a drop checker when you get a chance. It will tell you where you are.


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## Subaru4wd (May 6, 2011)

Thanks Guys. Yeah I will leave the CO2 disconnected for the rest of today, then connect it tonight, disconnect it tomorrow and so on.

Here is a picture of the bubble-bar i am using right now to diffuse the CO2:









The bubbles are very tiny when they come out... and they get pushed around quite a bit by my filter. I do have a nozzle I was going to connect to the filters output, and point towards the surface to create a wake. I am sure that will help to agitate the surface.

What really sucks is I need to perform a water change, and dont want to be using 7.2ph treated water in a tank that has close to 6.0 in it.


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## Gizmo (Dec 6, 2010)

Yeah, I would disconnect one of the two CO2 bottles or the entire system for a bit, and add a bubbler that you run at night. I've got a 1L yeast fermentation CO2 bottle injecting through a reactor into my 10 gallon, and I have to gas off with a bubbler at night since I can't turn off the CO2.


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## jrman83 (Jul 9, 2010)

The water change will not hurt anything even if there is a big difference in ph.


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## susankat (Nov 15, 2008)

I think you have it backwards, it needs on during the day and off at night. I just can't see how a diy system is causing so much problem on a tank that size. Most people will tell you that diy co2 does not help that much on anything larger than a 50 gal.

I would say something else is causing your problem and the co2 is just aggrevating it.


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## Subaru4wd (May 6, 2011)

can i get more info on these bubblers you guys are talkin about?


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## majerah1 (Oct 29, 2010)

I didnt realize it was on such a big tank.Yeah definatly should not be having this issue.


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## jrman83 (Jul 9, 2010)

Subaru4wd said:


> can i get more info on these bubblers you guys are talkin about?


The same bar you are using can be used (one like it), but hooked up to a air pump instead of your CO2.


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## Subaru4wd (May 6, 2011)

Oh... well yeah, i have had one of those. My current air pump has 2 outputs and it is running to a much larger air stone that is probably 12" long... its running 24/7 but I have a valve installed to keep the bubbles small.


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## Auban (Aug 8, 2010)

i wouldnt rule out CO2 as a problem. i used to use a DIY 1L bottle and a 2L bottle in one 75G tank. when they were at peak production my fish would all be at the top every morning. at one point, i saw my fire eel laying on the bottom breathing real hard and acting kind of stunned. when i tested the water, the ph was the only thing off. my water normaly sits at around 6.9, but it was so low in the morning that the test wouldnt read it. everything returned to normal after i pulled the CO2. it only took a couple hours with the lights on and no CO2 for my fish to return to normal activity. i think you are experiencing something similar. oh, my DIY bottles would run a lot more than two or three bubbles per second, more like 10-15. it almost matched the air pump i had on the tank.


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## jrman83 (Jul 9, 2010)

Auban said:


> oh, my DIY bottles would run a lot more than two or three bubbles per second, more like 10-15. it almost matched the air pump i had on the tank.


I think you mean per minute....I don't think any of my pressurized systems can hit 15 per second. My lowest rate on one tank is 120 per minute (2 per second) and the highest is 300 per minute (5 per second). I've seen pics of a guy with a 29g that had 4 2L bottles hooked to his tank and he had fish in it. Not sure if he was doing anything different when lights were out.


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## jrman83 (Jul 9, 2010)

Subaru4wd said:


> Oh... well yeah, i have had one of those. My current air pump has 2 outputs and it is running to a much larger air stone that is probably 12" long... its running 24/7 but I have a valve installed to keep the bubbles small.


If you've had a bubble wand in there all along and it is always on, then I doubt even more that CO2 is your issue. Bubblers will defeat what you're trying to do...which is load your tank with dissolved CO2. This is why most people will not use them concurrently and if they do use them, tend to do so using the previously mentioned method.


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## DocPoppi (Mar 4, 2011)

Are you using a canister filter? 
There was mention of surface agitation.... You need something going on to oxygenate the water.
My DYI C02 uses a small white airstone that I clip onto the intake of my filter, this helps dissolve the gas. 
Even with 2 bottles going and the size of your tank, I can't imagine C02 build up, free bubbling kinda wastes allot too.
But if there is not surface exchange for 02 and a raise in C02 you could have issues.
Your plants will survive a day or 2 of air bubbles, so do that and see how they do... If it's 02 you'll notice a change overnight.
By chance has any of the "mash" back flowed?


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## James0816 (Jun 19, 2009)

susankat said:


> I would say something else is causing your problem and the co2 is just aggrevating it.


Definately something other the CO2. Unless the fish are over at the bubbler taking "hits" off of it like it were a doobie or something. DOH! 

Seriously though, your CO2 is not the underlying issue here. Run your CO2 as normal and run an airstone at night when the lights go out for best results.

Highly, highly recommend a drop checker if you suspect the CO2 as being an issue. It's the only way you're gonna know for sure.

CO2 Drop Checker


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## Subaru4wd (May 6, 2011)

DocPoppi said:


> Are you using a canister filter?
> There was mention of surface agitation.... You need something going on to oxygenate the water.
> My DYI C02 uses a small white airstone that I clip onto the intake of my filter, this helps dissolve the gas.
> Even with 2 bottles going and the size of your tank, I can't imagine C02 build up, free bubbling kinda wastes allot too.
> ...


Yeah I am using a canister filter. I turned my airstone off this morning, and hooked the CO2 back up this morning when my lights came on.

Im pretty sold its not the CO2 itself, but something definatly was going on. This morning my angelfish was looking a whole lot better. Its eating again which I like seeing, and my tetra's havent been at the top of the tank since yesterday morning (when i found my other angelfish dead & this thread happend).

Im confident my plants will continue to live without CO2 in the tank. I only have 4 annubias, and 2 other plants. I have an assortment of bulbs scattered throughout the tank, but none of them have started to sprout.


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## Auban (Aug 8, 2010)

jrman83 said:


> I think you mean per minute....I don't think any of my pressurized systems can hit 15 per second. My lowest rate on one tank is 120 per minute (2 per second) and the highest is 300 per minute (5 per second). I've seen pics of a guy with a 29g that had 4 2L bottles hooked to his tank and he had fish in it. Not sure if he was doing anything different when lights were out.


actually, i mean 10-15 per second. there is no the two of us are seeing this big of a difference, so my guess is the valve i put on my DIY bottles to raise the pressure is making the bubbles come out faster and smaller... im not sure since im dont have one set up at the moment. i also keep my reactors at 90 degrees. they burn sugar fast. i still think the problem sounds exactly like what i have experienced. there are very few things that will cause all the fish in a tank to swim at the top, gulping air. that paired with the fact that the only fish that arent at the top are the ones that are dying or weak suggests that there is a problem with dissolved gasses. CO2 reactors also produce alcohol, which is an organic carbon that feeds anaerobic bacteria... the same bacteria that convert ammonia to nitrate. there isnt much alcohol in the bubbles, but i know from experience that if you anesthetize a lab mouse in pure CO2 and air it will fall asleep. if you use a yeast reactor as your CO2 source, it kills the mouse. i wouldnt rule out the reactors until i tested it, pull the lines for a day. if the problem goes away, then it has been identified. if it remains, test something else. too easy.


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## jrman83 (Jul 9, 2010)

Auban said:


> actually, i mean 10-15 per second. there is no the two of us are seeing this big of a difference, so my guess is the valve i put on my DIY bottles to raise the pressure is making the bubbles come out faster and smaller... im not sure since im dont have one set up at the moment. i also keep my reactors at 90 degrees. they burn sugar fast. i still think the problem sounds exactly like what i have experienced. there are very few things that will cause all the fish in a tank to swim at the top, gulping air. that paired with the fact that the only fish that arent at the top are the ones that are dying or weak suggests that there is a problem with dissolved gasses. CO2 reactors also produce alcohol, which is an organic carbon that feeds anaerobic bacteria... the same bacteria that convert ammonia to nitrate. there isnt much alcohol in the bubbles, but i know from experience that if you anesthetize a lab mouse in pure CO2 and air it will fall asleep. if you use a yeast reactor as your CO2 source, it kills the mouse. i wouldnt rule out the reactors until i tested it, pull the lines for a day. if the problem goes away, then it has been identified. if it remains, test something else. too easy.


I guess the fact of whether or not you could count that fast (I have a hard time counting 4bps or 240 bubbles per minute)matters or even if the system was capable.....I have killed fish at 5bps....therefore, easy to see why you were killing them if you really did see that. Although I have never tested, my systems are probably capable of a high rate like that, but then again they are under 35psi which is probably more than your plastic bottles are capable of. You should sell your mixture contents because you have THE highest bubble rate of ANY DIY mixture I have ever heard of. With that rate, why use pressurized systems?


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## Auban (Aug 8, 2010)

my job requires me to be able to count rounds fired at rates up to 900 rounds per minute. its not really that hard.... think small bubbles.


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## Subaru4wd (May 6, 2011)

Auban said:


> actually, i mean 10-15 per second. there is no the two of us are seeing this big of a difference, so my guess is the valve i put on my DIY bottles to raise the pressure is making the bubbles come out faster and smaller... im not sure since im dont have one set up at the moment. i also keep my reactors at 90 degrees. they burn sugar fast. i still think the problem sounds exactly like what i have experienced. there are very few things that will cause all the fish in a tank to swim at the top, gulping air. that paired with the fact that the only fish that arent at the top are the ones that are dying or weak suggests that there is a problem with dissolved gasses. CO2 reactors also produce alcohol, which is an organic carbon that feeds anaerobic bacteria... the same bacteria that convert ammonia to nitrate. there isnt much alcohol in the bubbles, but i know from experience that if you anesthetize a lab mouse in pure CO2 and air it will fall asleep. if you use a yeast reactor as your CO2 source, it kills the mouse. i wouldnt rule out the reactors until i tested it, pull the lines for a day. if the problem goes away, then it has been identified. if it remains, test something else. too easy.


All of my fish are showing signs of improvement since I disconnected the CO2. Now I am worried about the PH rising too rapidly. Im going to use CO2 for 8hrs a day and test my PH again tomorrow. 

Im also going to revise my system so I can use more bottles (i have been stocking up on 1liter bottles) and a valve system so i dont have to be unhooking tubes all the time.


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## Auban (Aug 8, 2010)

im glad your fish are getting better. i think a pressurized system is less dangerous because of the fact that there is no alcohol being produced. i know it doesnt take much to remove nitrates and phosphates in a marine system, and overdosing by just a little can crash the whole system.


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## jrman83 (Jul 9, 2010)

PH changes from CO2 should not affect your fish adversly. Mine go through a full point shift in 2-3 hours (lowering) and then back.


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## Subaru4wd (May 6, 2011)

jrman83 said:


> PH changes from CO2 should not affect your fish adversly. Mine go through a full point shift in 2-3 hours (lowering) and then back.


Than howcome everywhere else i read... and everything else I hear say as much as 0.3 change in ph over 24hrs is enough to kill some fish?

Regardless... Im not comfortable with it.


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## jrman83 (Jul 9, 2010)

A ph change caused by CO2 is a natural change and will not hurt your fish. Go to any planted tank website and ask what the rate of change is for their tanks from CO2. Most go to 20-30ppm CO2 within a a couple of hours - which would alter your ph from .5-1 point or more.

If that takes you out of your comfort level then you should not use CO2. That will happen on a daily basis. If I had to guess, even with your DIY system your ph is lowering faster than .3 in a 24hr period.

Don't take my word for it. Go here and ask The Planted Tank - Articles, Forums, Pictures, Links


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