# Tap Water Causing Extreme PH Swings



## EricP (Jun 12, 2010)

55 gal low tech, heavily planted
My tap water (deep well, 459ft) is coming up just loaded with CO2. On my first 50% water change the resulting acidic swing (6.8 to 6) killed 3 of my tetras.
MY question. If I filled a 30 gal container 3 or 4 days prior to a water change and used this instead of straight tap water would I be okay?
Thanks


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## wkndracer (Mar 14, 2009)

Should make a difference by allowing it to gas off. Fill an open top container (bowl or glass) and test it the following day (basic tap test) 

Run an air stone in the 30g change container.


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## lauraleellbp (Feb 3, 2008)

I strongly doubt it was the pH swing from CO2 that killed your fish- most people who inject pressurized CO2 into their tanks cause that same shift in their tanks 2x a day (as the CO2 comes on and off) with no impact on their fish.

I suspect it was something else in the water. So setting up a reservoir tank may or may not work... if it doesn't work, you may need to invest in an RO unit.


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## EricP (Jun 12, 2010)

lauraleellbp said:


> I strongly doubt it was the pH swing from CO2 that killed your fish- most people who inject pressurized CO2 into their tanks cause that same shift in their tanks 2x a day (as the CO2 comes on and off) with no impact on their fish.
> 
> I suspect it was something else in the water. So setting up a reservoir tank may or may not work... if it doesn't work, you may need to invest in an RO unit.


Here is what I am certain of after numerous tests. The water fresh out of my tap has a ph of 6 or lower. That is as low as my test kit gets.
Upon sitting on my counter for 18 hrs I test at 6.8.
So unless I am missing something, (which is entirely possible) it seems that a reservoir tank will at least solve the low ph problem.
As for the fish dying. I very rarely have fish die so I have to look at this as something other than coincidence


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## lauraleellbp (Feb 3, 2008)

Well, that pretty much confirms the theory that it's dissolved gasses in your water that are causing the pH swing.

It does nothing towards explaining what caused your fish to die, however, as pH shifts coming from dissolved CO2 would have had no effect on them.

It's pH shifts that are related to fluctuations in TDS (total dissolved solids) levels that are dangerous to fish.


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## Ian_4573 (Mar 29, 2010)

lauraleellbp said:


> Well, that pretty much confirms the theory that it's dissolved gasses in your water that are causing the pH swing.
> 
> It does nothing towards explaining what caused your fish to die, however, as pH shifts coming from dissolved CO2 would have had no effect on them.
> 
> It's pH shifts that are related to fluctuations in TDS (total dissolved solids) levels that are dangerous to fish.


Not to hijack a thread here but I am now confused. How can you "good" ph swings and :bad ph swings?
It seems to me that a PH of 6 or lower is bad for my fish no matter how it is caused. Particularly so when it is introduced to the tank in a shocking 50% water change and when it doesn't clear until a day and a half later.


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## wkndracer (Mar 14, 2009)

Doing a 50% WC is the temp really close?
Combination of pH and temp swing might combine causing stress.


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## 2wheelsx2 (Jan 27, 2006)

Did the fish look bloated? If there is a lot of offgassing, you could be dealing with "gas bubble disease", which I've never experienced, but only read about. But I read that it's more common with big volumes of water, as in ponds, and in coldwater fish (because of high solubility of gases.


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## Hilde (May 19, 2008)

I have read that injecting Co2 into tank with Kh below 3 can cause ph swings. What is your kh? I wonder if Seachem equilibrium or gh booster fert would help?


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## lauraleellbp (Feb 3, 2008)

Ian_4573 said:


> Not to hijack a thread here but I am now confused. How can you "good" ph swings and :bad ph swings?
> It seems to me that a PH of 6 or lower is bad for my fish no matter how it is caused. Particularly so when it is introduced to the tank in a shocking 50% water change and when it doesn't clear until a day and a half later.


Yes, in terms of fish health there ARE "good" and "bad" pH swings.

Again, it's TDS-related pH swings that cause problems for fish, NOT CO2-related. Otherwise every single person who injects pressurized CO2 into their tanks would experience fish die-offs every single morning and every single night, as the CO2 levels fluctuate and pH commonly shifts well over 1.0.

I keep on harping on about this because there are likely other water parameter issues here that are causing fish deaths, and just setting water out to outgas isn't likely to solve those problems.


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## Hoppy (Dec 24, 2005)

I agree with LauraLee. Many of us do 50% water changes every week, with no problems, usually with tap water that doesn't even closely match the tank water temperature. One thing that would bother the fish a lot is chlorine in the water. Do you add chlorine (hypochlorite) to your well water? Other possibilities might include copper in the well water or ammonia.

If CO2 in the water were the problem, the fish would cluster at the top of the tank, usually in a corner, appearing to be gulping air from the surface. Or. some fish would lay on the bottom, or lose their colors. Those are common reactions to too much CO2. And, it is the CO2 that is the problem, not the pH.


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## wkndracer (Mar 14, 2009)

Hilde said:


> I have read that injecting Co2 into tank with Kh below 3 can cause ph swings. What is your kh? I wonder if Seachem equilibrium or gh booster fert would help?


Equilibrium or gh booster will do nothing to raise KH as they contain no buffers and only raise general hardness. 
With tested 2dKH tank water I have a pH controller pushing pH down to 5.6 - 5.8 injecting CO2 with no effect to the fish.


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## EricP (Jun 12, 2010)

wkndracer said:


> Doing a 50% WC is the temp really close?
> Combination of pH and temp swing might combine causing stress.


WC change temperature is always controlled to 1 degeree plus or minus of tank temp


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## EricP (Jun 12, 2010)

lauraleellbp said:


> Yes, in terms of fish health there ARE "good" and "bad" pH swings.
> 
> Again, it's TDS-related pH swings that cause problems for fish, NOT CO2-related. Otherwise every single person who injects pressurized CO2 into their tanks would experience fish die-offs every single morning and every single night, as the CO2 levels fluctuate and pH commonly shifts well over 1.0.
> 
> I keep on harping on about this because there are likely other water parameter issues here that are causing fish deaths, and just setting water out to outgas isn't likely to solve those problems.


Don't lose patience yet! How long is theH recovery time on CO2 systems?
If it is every day, recovery must be fairly rapid. On my non CO2 system it takes well over 18 hrs just to climb out of 6.0 That is a long time.
PS the original 18 hrs I posted was wrong. Got my days mixed up.(since retirement it is happening a lot). It takes about 30 hrs to get back up to 6.8


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## lauraleellbp (Feb 3, 2008)

What do you mean by "recovery time"?

Have you checked the kH and gH of your well water versus that in your tank? If those levels are out of line, that's much more likely to be the source of your issues.


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## Hilde (May 19, 2008)

lauraleellbp said:


> It's TDS-related pH swings that cause problems for fish, NOT CO2-related.


I had read though that with Kh below 3 injecting Co2 would cause a Ph crash, not just a low fluctuation.


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## Hoppy (Dec 24, 2005)

Hilde said:


> I had read though that with Kh below 3 injecting Co2 would cause a Ph crash, not just a low fluctuation.


Any KH value above about 1 degree will buffer against a "pH crash". Low KH just means the pH will be lower than with high KH.


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## sajata (Aug 21, 2009)

My well water is 5.2 out of the ground. I do water changes all the time and don't have a problem. Dh/kh are 2

Sent from my DROIDX using Tapatalk


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## The_Finglonger (Jun 21, 2010)

Do yourself a favor and invest in an rodi unit, one of the best purchases I have ever made. 

I recommend something from the filter guys (http://www.thefilterguys.biz/) or something from bulk reef supply, can't go wrong with either.


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## Hilde (May 19, 2008)

The_Finglonger said:


> Do yourself a favor and invest in an rodi unit, one of the best purchases I have ever made.


It is only $265.00. Seems cheaper to just try fish that are hardy, like Dainos. 

How long have you had the tank up?


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## [email protected] (Jul 17, 2008)

New Jersey and a deep well. 
That says outside a city and maybe into farm country, or what used to be farm country. 

Do you have your water tested each year for nitrates and heavy metals? And Radon. 
Is the well casing far enough away from and sealed against pollutants getting into or along side it?


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## The_Finglonger (Jun 21, 2010)

Hilde said:


> It is only $265.00. Seems cheaper to just try fish that are hardy, like Dainos.
> 
> How long have you had the tank up?


$265?

I got mines for $160, a 3-stage w/ DI.


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## EricP (Jun 12, 2010)

lauraleellbp said:


> What do you mean by "recovery time"?
> 
> Have you checked the kH and gH of your well water versus that in your tank? If those levels are out of line, that's much more likely to be the source of your issues.


Tank: GH 2 drops (0-50ppm) KH 2 drops (0-50ppm)
Fresh from tap: GH 2 drops (0-50ppm) KH 2 drops (0-50ppm)
After sitting on counter 2 days No change


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## lauraleellbp (Feb 3, 2008)

So very soft water.... hmmm

How long had your tank been set up when you did the 50% change and experienced the deaths?

Have you double-checked ammonia, nitrite, and nitrates?


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## wkndracer (Mar 14, 2009)

EricP said:


> Tank: GH 2 drops (0-50ppm) KH 2 drops (0-50ppm)
> Fresh from tap: GH 2 drops (0-50ppm) KH 2 drops (0-50ppm)
> After sitting on counter 2 days No change


WOW! RO water straight out of the ground! (well,,, almost :icon_roll)


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## 2wheelsx2 (Jan 27, 2006)

wkndracer said:


> WOW! RO water straight out of the ground! (well,,, almost :icon_roll)


Yup, awesome stuff. We got it here where I live: GH and KH = 1 out of the tap. What's not so awesome is having to add GH booster all the time for the fish and plants. Sometimes, too much of a good thing....


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## EricP (Jun 12, 2010)

lauraleellbp said:


> So very soft water.... hmmm
> 
> How long had your tank been set up when you did the 50% change and experienced the deaths?
> 
> Have you double-checked ammonia, nitrite, and nitrates?


Tank set up for 8 months now. Nitite has consistently tested 0.
Nitrates are always controlled at 10-20 ppm
Phosphate always controlled between 1 and 0
I'm starting to look at other things now concerning fish death. The three neon tetras that died were recently added to increase the school size of my first tetras which were original stocking back in April. I can tell this because they were all a bit smaller.
Perhaps just the shock of the water change (fish always get a bit frantic) sent already weak fish to their demise. Anyway, most of you guys convinced me that I shouldn't worry about the PH shift from 6.8 to below 6 and then back up to 6.8 2 day later.
I still may add a resevoir tank just to correct the PH and also enable me to dose right into the resevoir and be done with it


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## wkndracer (Mar 14, 2009)

Quote:
Originally Posted by *wkndracer*  
_WOW! RO water straight out of the ground! (well,,, almost :icon_roll)
_


2wheelsx2 said:


> Yup, awesome stuff. We got it here where I live: GH and KH = 1 out of the tap. What's not so awesome is having to add GH booster all the time for the fish and plants. Sometimes, too much of a good thing....


You should still feel *very* lucky with that water quality. My well is deep but still full of Ca, tannins, and somehow what H2O treatment company's call 'organic iron' (what ever :icon_redf). 
My whole house water system is a Kinetico using salt for regen. Then I've got a 6 stage RO unit w/booster pump dumping into a 105g aerated reservoir to take the remaining minerals and salt ions out. 198ppm (on average inlet TDS) down to 3-4ppm TDS product. 
THEN I GET TO ADD A GH BOOSTER for all my tanks so your getting off WAY cheaper LOL.


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## Hilde (May 19, 2008)

wkndracer said:


> Quote:
> Originally Posted by wkndracer
> 
> 
> ...


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## Hilde (May 19, 2008)

EricP said:


> The three neon tetras that died were recently added to increase the school size of my first tetras.


Neons aren't' as hardy as the use to be. You might try acclimating them for an hour.


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