# how much can diy co2 reduce ph by?



## apisto420 (Apr 24, 2010)

i just started up my low tech planted again.. i have 2 diy co2 bottles(1.5litre) in my 46 gallon bow front coming out from air stones and i only have less than 1 watt per gallon.. will this reduce my ph by alot? how much can it reduce ph to? should i even put in co2 into my tank?

almost forgot to mension that im dosing kno3, kh2po4 and some flourish comprehensive supplement, but very low dosage since im low light


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## lauraleellbp (Feb 3, 2008)

Your pH drop will depend on how buffered yor tank is.

I'd recommend a drop checker with a calibrated 4dkH solution to get a more accurate CO2 estimation.

Your tank is on the large side for DIY CO2, but since you're running 2 bottles and only low light, you can probably make it work if you've got good flow.


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## Cbwmn (Nov 30, 2007)

For a couple of years, I used two heavy duty one gallon jugs on my 46 gallon.
I started a new batch in one jug each week. Injected through my XP2 canister.
I could easily get down to the 6.6 pH range.
I got tired of all the sugar/yeast mixing and went pressurized a year ago.

IMO, drop checkers only give you an approximate range of concentration depending upon the shade of yellow indicated.
However there are a lot of folks on this forum that are smarter than I am and they swear by DC’s.
I may be foolish, but now I rely on a pH controller.
Good luck
Charles


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## lauraleellbp (Feb 3, 2008)

The problem with going by pH is that there are so many other things that can alter pH readings besides just dissolved CO2.


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## Cbwmn (Nov 30, 2007)

lauraleellbp said:


> The problem with going by pH is that there are so many other things that can alter pH readings besides just dissolved CO2.


I’m well aware of that.
The OP asked how much can diy co2 reduce ph by?
I was stating my opinion on the accuracy of DC’s.
Do you consider a DC to be an accurate indication of Ph?
Or CO2 concentration?
I do not. 
Regards 
Charles


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## lauraleellbp (Feb 3, 2008)

No, I think a drop checker will give a better idea of real-life CO2 saturation over an idealized mathematical forumula based on pH alone.


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## oldpunk78 (Nov 1, 2008)

apisto420 said:


> i just started up my low tech planted again.. i have 2 diy co2 bottles(1.5litre) in my 46 gallon bow front coming out from air stones and i only have less than 1 watt per gallon.. will this reduce my ph by alot? how much can it reduce ph to? should i even put in co2 into my tank?
> 
> almost forgot to mension that im dosing kno3, kh2po4 and some flourish comprehensive supplement, but very low dosage since im low light



i would think that diy co2 on 46g is really just a waste of sugar. i also think that it would create some instability in the co2 levels in your tank - which is something that you don't want. you are probably going to be better off with out it. don't worry about the ph.


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## apisto420 (Apr 24, 2010)

oldpunk78 said:


> i would think that diy co2 on 46g is really just a waste of sugar. i also think that it would create some instability in the co2 levels in your tank - which is something that you don't want. you are probably going to be better off with out it. don't worry about the ph.


yeah i think im jus not gona use co2, i only have .8 watts per gallon anyways... for now ill jus leave the airstones near the top of the tank since its already set up for now, or maybe i should just set 1 bottle only and with the airstone lower in the tank.. i do want a forest for my tank since my fish likes it. so im aiming to have a highly planted low tech tank.. 1 bottle of diy co2 must benifit for a highly planted tank right, more plants = need more co2

i just wanted to know if the co2 bottles can reduce the ph with big drops which would kill my fish, since this is a bigger tank the diy co2 wouldnt effect the ph by much correct? let me know if i should just set up 1 bottle for safety of the fishes


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## OverStocked (May 26, 2007)

CO2 related pH swings will NOT affect your fish. They are not the same as normal pH swings. What you need to worry about is KH and GH and CO2 will NOT effect this.

Again, CO2 related pH swings are irrelevant and will not effect your fish.


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## apisto420 (Apr 24, 2010)

over_stocked said:


> CO2 related pH swings will NOT affect your fish. They are not the same as normal pH swings. What you need to worry about is KH and GH and CO2 will NOT effect this.
> 
> Again, CO2 related pH swings are irrelevant and will not effect your fish.


 
im kinda confused.. so the DIY CO2 bottles will not affect the PH of the water? hm i always thought it did.. well im going to put the CO2 airstones to the bottom of the tank to get full potential of the CO2 then!

were you guys always talking about the PH of the sugarwater in the CO2 bottles?


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## OverStocked (May 26, 2007)

apisto420 said:


> im kinda confused.. so the DIY CO2 bottles will not affect the PH of the water? hm i always thought it did.. well im going to put the CO2 airstones to the bottom of the tank to get full potential of the CO2 then!
> 
> were you guys always talking about the PH of the sugarwater in the CO2 bottles?


CO2 will change pH, however, CO2 induced pH swings are not the same as a pH swing in a tank without co2. CO2 induced pH swings are caused by carbonic acid. CO2 swings in normal tanks are caused by a fluctuation in KH and that is what is bad. Fish are sensitive to KH and GH, but pH is nearly irrelevant for most purposes. As long as the KH and GH of you water stays consistent, the pH is not important.

DIY co2 will change pH some, though not much. None the less, it isn't important... because... CO2 related pH swings are NOT IMPORTANT.


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## Diana (Jan 14, 2010)

What is the KH of your water?
Do you have any other buffers in there? (Perhaps a phosphate buffer, or peat moss...)






















If the KH is pretty low (like under 3 degrees) then the DIY CO2 might cause some pH variation. Very little. You simply cannot add that much CO2 via yeast to do that much to the tank. 
Also, pH is NOT NOT NOT very critical to the fish. It MAY indicate that something else is changing, and that something else might be of interest, and more important to the fish. For example, if the TDS is changing THIS is important to the fish. Some of the materials measured by a TDS meter can affect the pH, so if the pH is changing in the water, look into what might be causing it. 
Forget pH as a stand alone value that is very important in itself. 


I have used DIY CO2, with larger bottles, and more of them on the tank, and the GH, KH and TDS are stable in these tanks. Never mind the pH. The fish do not mind.


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## apisto420 (Apr 24, 2010)

Diana said:


> What is the KH of your water?
> Do you have any other buffers in there? (Perhaps a phosphate buffer, or peat moss...)
> 
> 
> ...


i just have some wood in my tank not sure what kind. dont know what the KH is i have a kit but im missing the KH booklet.. so i have no idea how to use it.. i will eventualy find it probably..


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## hybridtheoryd16 (Mar 20, 2009)

Whether Ph related or not I beleive to are thinking about the safety of your tank inhabitants.

In that case just watch and observe the fish and the PH for a few days once it gets going. If infact you do get a large ph drop then you have grounds for caution.

If your using bakers yeast then it would take alot more than what you have to gas the fish to harm. 

I have used 1/4tsp champagne yeast, 1/4tsp yeast nutrient, and 2 cups of sugar in a 2ltr jug. And killed some lemon tetra's in a 20g due co2 concentration. Wine and champagne yeast are alot more potent and should be used with caution. IMO


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## OverStocked (May 26, 2007)

hybridtheoryd16 said:


> Whether Ph related or not I beleive to are thinking about the safety of your tank inhabitants.
> 
> In that case just watch and observe the fish and the PH for a few days once it gets going. If infact you do get a large ph drop then you have grounds for caution.
> 
> ...



I will say it again... CO2 induced pH swings WILL NOT harm fish. You might suffocate them with co2(not diy...) but a pH swing caused by CO2 will NOT harm fish. You are more likely to have inadequate surface agitation and thus inadequate oxygen in the water. 

KH and GH are the important values and co2 induced pH changes do not touch them. THe problem with "normal" pH swings is that they are usually caused by a change in KH, and fish are sensitive to changes in KH.


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## lauraleellbp (Feb 3, 2008)

I THINK the point that hybridtheory is making is that if there's a very dramatic pH drop, the tank may not be well buffered... and that MIGHT be a concern. 

Apisto- what brand kH test kit do you have?


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## Cbwmn (Nov 30, 2007)

over_stocked said:


> CO2 related pH swings will NOT affect your fish. They are not the same as normal pH swings. What you need to worry about is KH and GH and CO2 will NOT effect this.
> 
> Again, CO2 related pH swings are irrelevant and will not effect your fish.


I disagree. 
Injecting too much CO2 will kill livestock.
Charles


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## lauraleellbp (Feb 3, 2008)

Cbwmn said:


> I disagree.
> Injecting too much CO2 will kill livestock.
> Charles


Agreed, but the issue there is CO2 poisoning, not the pH swing.

In a very hard/buffered tank you can have CO2 poisoning w/out the pH moving much at all... 

Difference between correlation and causation.


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## Diana (Jan 14, 2010)

Also, it is just about impossible to add that much CO2 using DIY methods. Maybe several bottles on a very small tank, but the original question was based on two bottles of 1.5 liters on a large tank. No way are you going to poison the tank with that. (Unless you dump yeast, sugar and all into the tank- happened to me, which is why I use separator bottles)

Instructions for AP KH and GH tests:
Fill tube to mark with tank water. 
Add reagent one drop at a time and shake. 
Every drop you add means one German degree of hardness. 
You are looking for a color change. When the water is really hard the test will stay blue for quite a few drops, then will look sort of 'off' for one drop, then will turn yellow. (at least that is the way mine behaves). Very soft water may turn yellow with the first drop.

GH changes from yellow to green, but the change is pretty subtle. View it against a white background, not against anything that is green. The test tube will pick up that green from the surroundings, and it is hard to tell. 
Looking down from the top can be an easier way to tell.


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## Lee (Feb 13, 2007)

"Fish are sensitive to KH and GH, but pH is nearly irrelevant for most purposes." 

do you have any evidence of this at all? sound ridiculous.


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## OverStocked (May 26, 2007)

A general understanding of water chemistry will be needed to understand. Ph in and of itself is not important. The reason we even pay attention to ph is because it could be and indication of kh changes. 

I have 15 years of keeping fish and can give you a variety of others who say the same. Ph value is not important. General and carbonate hardness are, and thus pH is a partial indicator of kh. 

The concern here is co2 induced ph changes are not related to kh so they are not the same as normal ph swings. 

Researching basic water chemistry will give you a good understanding of why ph is not significant. 



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## Lee (Feb 13, 2007)

"Each species of fish has its own very narrow range of pH preference and levels outside of this range will cause health problems. For example, koi prefer a range between 7 and 8.5, while some tropical fish prefer water that is slightly acidic. There are several ways that pH can affect fish health


High acidity or alkalinity can cause direct physical damage to skin, gills and eyes. Prolonged exposure to sub-lethal pH levels can cause stress, increase mucus production and encourage epithelial hyperplasia (thickening of the skin or gill epithelia) with sometimes-fatal consequences.


Fish also have to maintain their own constant internal pH. Even small fluctuations of blood pH can prove fatal. Extreme external or water pH can influence and affect blood pH, resulting in either acidosis or alkalosis of the blood."


http://www.fishdoc.co.uk/water/pH.htm


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## OverStocked (May 26, 2007)

> "Each species of fish has its own very narrow range of pH preference and levels outside of this range will cause health problems. For example, koi prefer a range between 7 and 8.5, while some tropical fish prefer water that is slightly acidic. There are several ways that pH can affect fish health
> 
> 
> High acidity or alkalinity can cause direct physical damage to skin, gills and eyes. Prolonged exposure to sub-lethal pH levels can cause stress, increase mucus production and encourage epithelial hyperplasia (thickening of the skin or gill epithelia) with sometimes-fatal consequences.
> ...


In wild fish this might be true. However, stability is significantly more important than some target ph. 

I'm not sure you understand what you quoted. The simple fact is kh is what contributes to water being alkaline or acidic. Ph changes caused by co2 DO NOT RELATED TO KH. Your quote even indicates fish can actually tolerate a rather large range. 

I can sit and turn co2 on and off over and over and have zero effect on fish as long as I don't suffocate them with way too much co2. The pH bounces when you do this yet somehow the fish are uneffected? Could it be the constant kh?


I understand you are going off what you've read, but I swear on my right leg that pH changes unrelated to kh changes are irrelevant and ph changes in normal circumstances or only important because of a lack of kh or a kh change. 

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## Lee (Feb 13, 2007)

ill go with the conventional and common knowledge that PH is critically important to fish (all animals) health over you swearing on your right leg.


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## OverStocked (May 26, 2007)

> ill go with the conventional and common knowledge that PH is critically important to fish (all animals) health over you swearing on your right leg.


What common knowledge? You don't even seem to understand the grossly generalized article you linked. Spend a little time searching this forum. You will find people like Tom Barr and others saying the exact same thing. 

Most commercially bred fish only need stability, and as long as kh and gh are stable, co2 related ph swings are completely irrelevant. Search this forum. 




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## lauraleellbp (Feb 3, 2008)

The key word here is "extreme."

And I'll agree that pH IS an important parameter to consider and keep an eye on in a tank- because it can be indicative of so many other issues that are more difficult for the average hobbyist to observe or test for. 

However, in general, in a "normal" community planted tank, given STABLE water parameters, the vast majority of fish that we hobbyists commonly keep are very able to adapt to pHs ranging from 6.5 to 7.5, and many are hardy even well outside those ranges.

IE- GBRs have a reputation of being a delicate fish very susceptible to water parameter issues and needing soft, acidic water. My own well water pH runs 7.6-7.8 and my hardness is off the charts, yet my GBRs spawned every 2 weeks like clockwork. As they were in a community tank and the eggs were always eaten I do NOT know if the eggs would have hatched or fry would have survived given my water parameters, but the adults never displayed any issues at all. 

And pH fluctuations from dissolved gas content (ie CO2) are a very different ball of wax from those resulting from fluctuation in dissolved solids- it's been demonstrated repeatedly that CO2-driven pH changes have little to no impact on fish. There are plenty of hobbyists on this forum whose _*pH will shift as much as 1.0 or more twice a day, every day*_, as their pressurized CO2 switches on and off- yet no negative impact on the fish. Healthy, good color, spawning, raising successive generations of fry...


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## hybridtheoryd16 (Mar 20, 2009)

over_stocked said:


> I will say it again... CO2 induced pH swings WILL NOT harm fish. You might suffocate them with co2(not diy...) but a pH swing caused by CO2 will NOT harm fish. You are more likely to have inadequate surface agitation and thus inadequate oxygen in the water.
> 
> KH and GH are the important values and co2 induced pH changes do not touch them. THe problem with "normal" pH swings is that they are usually caused by a change in KH, and fish are sensitive to changes in KH.


So if you add enough co2 to lower the tanks PH number down to say 4-5PH. And because of that your tanks biological system shuts down. Then the resulting ammonia/ammonium/nitrite wouldn't harm your fish? 

Thats why i said he would have grounds for caution if he seen a severe PH drop. There are alot of things PH values effect.


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## OverStocked (May 26, 2007)

> > I will say it again... CO2 induced pH swings WILL NOT harm fish. You might suffocate them with co2(not diy...) but a pH swing caused by CO2 will NOT h
> 
> 
> 
> ...


At this point co2 poisoning would have done the trick if you were at a reasonable ph to start. Though I have seen tanks with a ph of 5.5 with no problems. 

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## lauraleellbp (Feb 3, 2008)

hybridtheoryd16 said:


> So if you add enough co2 to lower the tanks PH number down to say 4-5PH. And because of that your tanks biological system shuts down. Then the resulting ammonia/ammonium/nitrite wouldn't harm your fish?
> 
> Thats why i said he would have grounds for caution if he seen a severe PH drop. There are alot of things PH values effect.


And if the CO2 DIDN'T kill the fish outright, at that pH any ammonia would most likely be converted quicky into ammonium- so less toxic, and likely not a lethal issue.


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## apisto420 (Apr 24, 2010)

> --------------------------------------------------------------------------------
> 
> Also, it is just about impossible to add that much CO2 using DIY methods. Maybe several bottles on a very small tank, but the original question was based on two bottles of 1.5 liters on a large tank. No way are you going to poison the tank with that. (Unless you dump yeast, sugar and all into the tank- happened to me, which is why I use separator bottles)
> 
> ...


will these instructions work for my tester?

i have this kit with these 2 little bottles cept im missing the book.. how great.. i checked my ph and looked to be around 6 on the ph low tester.. kinda weird cause i thought my tap put out aroun 7.5 or something like that


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## apisto420 (Apr 24, 2010)

ok guys i just got the tester and only needed 1 drop in each tube which is 17.9 ppm gh/kh what should i do now? co2 is harmless or no?


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