Can pH swing kill fish?

[Neptune's Neighborhood]

I thought this was a great topic to bring out into the open from this thread.
Here, Rod backed up his claim earlier in the thread -

http://www.tbas1.com/Exchange/The New England 11.pdf

Everyone should read this!

The article by Joe Gargas....

Now, I can't argue that Joe doesn't know what he's talking about. He has a proven track record, that much is crystal clear.

My question is - is the assertion that because pH doesn't specifically measure anything, it can't actually be a cause that has an effect? Instead, the issues are related to something that is measured in a different way and pH is only a possible indicator that something is changing?

What I mean is, if we take pH to specifically indicate the availability of hydrogen ions, does this not directly affect osmoregulation and hemeostasis in the fish? I know fish can survive prolonged changes and acute changes, within the species' specific tolerance range, there is no doubt that this happens both in captivity and in the wild. But, with rapid changes in the availability of hydrogen ions, won't the fish need to adapt physiologically?

Specifically, as the pH number lowers, there are more free hydrogen ions in the solution, of which are toxic to to fish (internally, not externally). This would translate into more hydrogen-charged salts, acids, etc in the water which the fish needs to survive. As the fish intakes molecules from the water, its cells will need to work harder at separating the hydrogen ions to release them from the body. In turn, it will become more difficult for the cells to maintain hemeostasis and osmoregulation, both of which are essential functions.

Is the argument that scientifically, pH cannot affect change and is a poor indicator of real changes, and we, as the hobbyists, need to distinguish the myth from the reality?

 

[Rod]

This IS what happens.....particularly with soft water fish

Joe blow measures pH....he then believes its too high
So he adds Fred Bloggs's pH down.....he measures it again...it's ok
He measures tomorrow...high again....so he adds more pH down
And the sarga continues all the time he is increasing TDS ....eventually the ph crashes because all the buffering is gone.....the osmotic pressure is so great it kills his fish....he doesn't measure or understand TDS....so what killed his fish?

Lower pH......rubbish

Soft water fish need soft water....soft water + ketapang or peat = lower pH
Worry about TDS/ conductivity .....forget pH

I suggest everyone should read Joe's article several times...digest it....it's so true!

 

[Neptune's Neighborhood]

General hardness being mostly calcium and magnesium for our purposes and carbonate hardness being mostly carbonate and bicarbonate. My understanding is that the carbonate and bicarbonate ions are poor conductors.

If one were to use electrical conductivity (microSiemens) as their parameter for monitoring, how would this translate into monitoring carbonated hardness or pH? Would you need to instead measure PPM for each type of ion that you're testing?

We can't deny that species have ranges of acceptable pH that we need to stay within, so what type of change in EC (or PPM) would translate into an indication that parameters are going awry? It seems possible that EC could stay steady while KH and pH alter..

Pardon my ignorance.

 

[dw1305]

Hi all,
The problem with pH is that it is a both a log10 scale and a ratio. pH doesn't tell you anything about amounts of acids (H+ ion donors) or bases (H+ ion acceptors), just their ratio.

In water low in solutes you can get large changes in pH which reflect very small changes in water chemistry.

This is the situation during photosynthesis, where changes in the ratio of dissolved CO2 (of which a tiny % is as carbonic acid (H2CO3)) and DO (dissolved oxygen) (the base in O-H) cause large diurnal swings in pH.

My understanding is that the carbonate and bicarbonate ions are poor conductors.

This is to do with carbonate buffering and solubility. Sodium bicarbonate (NaHCO3) is a soluble salt and a base, and will cause both conductivity and pH to rise. Calcium carbonate is much less soluble and the amount of HCO3- ions will depend upon the level of dissolved CO2.

Have a look at these threads, and particularly "Regani's" posts <http://www.apistogramma.com/forum/index.php?threads/700-liter-amazone.13197/>, <http://www.apistogramma.com/forum/index.php?threads/keeping-low-ph.12720/#post-69837> & <http://www.apistogramma.com/forum/index.php?threads/conductivity.13258/#post-71747>

cheers Darrel

 

[gerald]

Conductivity doesn't really translate at all to pH, hardness, or alkalinity. If conductivity is very low (less than 50 uS), then hardness and alkalinity must also be low (since hardness and alkalinity rely on ions). But other common ions like Na+, K+, Cl-, SO4- can be abundant (high conductivity) regardless of pH, hardness, or alkalinity levels. So you're right, alkalinity can get all used up and pH can drop fast without any obvious change in conductivity.

CaCO3 is slightly MORE conductive than NaCl (by weight). 20 mg/L of NaCl gives a conductivity of about 42 uS, whereas 20 mg/L of CaCO3 gives a conductivity of about 50 uS. If CaCO3 was the only dissolved substance present your water, then you could estimate hardness and alkalinity by measuring conductivity. But in a fish tank, river or lake, it's obviously not the only ion present.

If one were to use electrical conductivity (microSiemens) as their parameter for monitoring, how would this translate into monitoring carbonate hardness or pH? Would you need to instead measure PPM for each type of ion that you're testing?

We can't deny that species have ranges of acceptable pH that we need to stay within, so what type of change in EC (or PPM) would translate into an indication that parameters are going awry? It seems possible that EC could stay steady while KH and pH alter... Pardon my ignorance.