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I hooked up Co2 and my Ph dropped from over 7.8 to 7.2 in 12 hrs My kh is 70 Ppm and according to a calculator that puts my co2 at 7 ppm. Could any of this kill a fish. I have a Ram that was perfactly normal yesterday and I noticed a Serpae Tetra with a black area developing over his eye. Any suggestions?
 

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A pH drop due to CO2 injection won't kill fish. Now if the CO2 goes above 35ppm, you may start to see the fish gasping at the surface, but 7ppm is no problem.
 

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A pH drop definitely can kill fish, but it would have to be a very rapid drop. A .6 drop over 12 hours isnt going to kill anything.
No, this is not correct in the context the poster asked.
The drop or rise in pH is due to CO2 injection(which is the issue here).

I do 60-80% water changes and the pH changes a full 1.0 unit in 20-30 minutes or less. Never lost even the most sensitive of species for shrimps or fish. This has been occurring for decades now on virtually everyone's tank that does large water changes with tap water..........

Conclusion: it cannot be due to the CO2 gas.
CO2 is not a salt, large rapid changes in the salt content of water(KH mostly) will influence pH which is an indirect measure. That can harm fish, change due to solely CO2 ppm does not.

If it did, we'd all have to add CO2 to the new water before refilling the aquarium, no one does this.

If two tap water's with the same CO2 have a pH difference 1.0 full unit then yes, that could kill fish, but that's not due to CO2, that's due to the KH/other salts etc.

Most web advice is based on that, not enriched CO2 systems.
Enrichment with CO2 changes that rule.

That leads to confusion and myths.
However, it also allows use to look at what is the real issue, not pH so much, rather the salts and osmotic changes fish go through when being transfered.
This way we measure what is important to fish health, not the indirect measures that may or.... may not............ have any importance for us.



Regards,
Tom Barr
 

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Other than to make it more complicated, you basically just said the same thing as i did.

The OP said...just hooked up my co2 system, pH dropped from 7.8 to 7.2 in 12 hours...can that harm my fish...???

My answer... yes, a sharp pH drop can kill fish, but .6 in 12 hours is fine, its not going to kill anything. That is directly related to what was asked about, and totally with in the context.

You just added a bunch of info that wasnt needed, and i think YOUR reply wasnt in the context of what the OP asked. So there!!! lol
 

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VisionQuest: there is an extreme difference in what he said, and what you implied. Simply accept that (for if Tom's explaining it didnt make u see it, you just wont).

Also, in the future. If Tom Barr says it. It must be true. This is something I have learned.

SO THERE.
:hihi:
 

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VisionQuest: there is an extreme difference in what he said, and what you implied. Simply accept that (for if Tom's explaining it didnt make u see it, you just wont).

Also, in the future. If Tom Barr says it. It must be true. This is something I have learned.

SO THERE.
:hihi:
In what i implied?? That a drastic swing in pH CAN kill fish??? Or that a drop of .6 in pH over 12 hours wont kill anything??? I wasnt trying to be argumentative in the least, i was really just kind of poking fun at Tom, just for funs sake, and think you are more or less doing the same to me. I shouldnt wouldnt and couldnt EVER try to win a technical argument with Tom. He forgot more this week than i have learned so far, im sure! lol

But the OP asked if the co2 injection or the drop in pH was harming his fish, and i basically said no. Tom got much more in depth and took it to a whole new level, but still basically said no.

Am i wrong??? :help:
 

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So if a took a ten gallon tank full of fish and split the water between two 5 gallon tanks and added CO2 to only one. Drop the pH by .6 with CO2 and then transfer all the fish they'd be fine?


SteveU
 
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