Sudden Drop in PH

Wanna bet? A rapid rise from 6 to 8 is pretty much what happens when the rainy season hits in the tropics. Rapid drops are much more stressful. And the same holds true for TDS as well, rapid lowerings are much better tolerated than rapid rises.
Box of Discus (few Hundreds) can run few thousand dollars @ wholesale level.. I dont know about you but I am not millionnaire nor do I wish to jeopardize their lives when I can surely avoid mishaps with little extra efforts given.

I guess you have not seen the result of rapid increase or decrease in pH??? (actual addition of addition of base/acid).

It all depends on the species of fish and/or individual fish.

Since you happened to insist on importance of TDS, can you explain why it is so important? How they affect fish?
 
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Box of Discus (few Hundreds) can run few thousand dollars @ wholesale level.. I dont know about you but I am not millionnaire nor do I wish to jeopardize their lives when I can surely avoid mishaps with little extra efforts given.

I guess you have not seen the result of rapid increase or decrease in pH??? (actual addition of addition of base/acid).

It all depends on the species of fish and/or individual fish.

Since you happened to insist on importance of TDS, can you explain why it is so important? How they affect fish?

I covered this in my last - osmosis.

I have seen the result of rapid decrease of pH. It happens when I turn on the CO2. The result is bugger all, apart from the plants pearling. However, if pH drops suddenly because you add a strong acid like HCl, then you will see problems because it will lower the TDS by turning the bicarbonate into CO2:

HC3O- + HCl → Cl- + H2CO3

H2CO3 → H2O + CO2(g)
 
Interesting discussion and as always informative.

Bob,
test your source water. get an idea what you have to work with.
I would not whole heartedly, rely soley on your ph probe at this point.
I also suggest you find a test to measure kh/gh.
I do agree that turning the CO2 off should cause a rise in pH not a drop.
 
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I covered this in my last - osmosis.

I have seen the result of rapid decrease of pH. It happens when I turn on the CO2. The result is bugger all, apart from the plants pearling. However, if pH drops suddenly because you add a strong acid like HCl, then you will see problems because it will lower the TDS by turning the bicarbonate into CO2:

HC3O- + HCl → Cl- + H2CO3

H2CO3 → H2O + CO2:Primary reaction

You should know that H2CO3 is in equilibrium with HCO3- + H+ which is in equilibrium with CO3- + H+. Equlibrium will shift depending on pH and other factors such as TDS, etc etc, I think.. Wow, going back to Chem 101. Inorganic much more difficult concept to comprehend than Organic chemistry as far as reaction mechanisms IMHO.

If you understand constant equilibrium shift thru oout the day and also understand Osmosis, then you should understand the importance of gill filament which functions as respiratory, excretory + ioninc exchange sites (TDS: Osmosis and Diffusion Gradient)
 
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I covered this in my last - osmosis.

I have seen the result of rapid decrease of pH. It happens when I turn on the CO2. The result is bugger all, apart from the plants pearling. However, if pH drops suddenly because you add a strong acid like HCl, then you will see problems because it will lower the TDS by turning the bicarbonate into CO2:

HC3O- + HCl → Cl- + H2CO3

H2CO3 → H2O + CO2:Primary reaction

You should know that H2CO3 is in equilibrium with HCO3- + H+ which is in equilibrium with CO3- + H+. Equlibrium will shift depending on pH and other factors such as TDS, etc etc, I think.. Wow, going back to Chem 101. Inorganic much more difficult concept to comprehend than Organic chemistry as far as reaction mechanisms IMHO.

If you understand constant equilibrium shift thru oout the day and also understand Osmosis, then you should understand the importance of gill filament which functions as respiratory, excretory + ioninc exchange sites (TDS: Osmosis and Diffusion Gradient)
I think that's the point Karl is trying to make. Problems occur because the addition of an acid/base causes a change in TDS as well as pH...but it's the TDS change that causes the problems, not the differing H+ concentrations.
 
My point is that there is no difference in "Adding acid/base (w/o going into Normality & Molarity in details) to tank to drop/raise pH suddenly and removing fish from tank to tank with drastic difference in pH".
 
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