Why do sites report PH ?

[anewbie]

One thing i never understood is why everyone reports PH associated with fishes. My crude understanding is PH is a by product of water chemistry and fishes are more concern with water chemistry then the actual PH. Reporting PH constantly leads to confusion with people trying to lower the ph without actually changing the chemistry.

Now TDS is only part of the chemistry as it goes to the break down between KH/GH which can be partially guess by PH (though this comment is inaccurate).

So either my understanding is fundamentally broken or PH should never have been introduced to the hobby.

 

[Mike Wise]

It is just a manner of showing completeness. For some water sources it is more important than others, especially if one is interested in keeping breeding. pH is important for fish from hard water sources like those from rift lakes in Africa compared to softwater species like apistos.

 

[anewbie]

It is just a manner of showing completeness. For some water sources it is more important than others, especially if one is interested in keeping breeding. pH is important for fish from hard water sources like those from rift lakes in Africa compared to softwater species like apistos.

My point is the ph actually a useful number or is tds/kh/gh sufficient. The issue is that ph can naturally drift and in the aquarium artifical means can radically change ph - with my favorite example being take 500 tds water and pump in co2 until the ph is 4.7. However relatively speaking tds/kh/gh are constants esp in the wild. While in the aquarium this and that can cause them to drift and we can change them artifiically they are relatively stable when measured in days unless we are adding to one (accidentally or intentionally) or changing one (adding acid or similar).

Another way of asking this is - if the tds is 5 does it matter if the ph is 4.7 or 7.3 (even if we expect it to be much lower than 7.3) ?

 

[dw1305]

Hi all,

.... Another way of asking this is - if the tds is 5 does it matter if the ph is 4.7 or 7.3 (even if we expect it to be much lower than 7.3) ?

I don't think it does, my opinion is that pH isn't a very useful measurement in water with very low solute levels.

I prefer conductivity as a measurement, it tells you that any addition of acid - H+ "proton donors" will lower pH. It is less "useful" than pH, but much more straightforward to measure.

Making water harder, and more alkaline, is easy. Once you get above about 4 dKH? The pH rises to pH8, so you really need an estimation of dKH as well.

Cheers Darrel

 

[anewbie]

The motivation for this question is new fish keepers are often confused by ph - they keep trying to lower the ph without fundamentally changing the water chemistry - and this raises the question if you have good water chemistry does it really matter what the ph actually measures even in advance case. I keep reading that xyz require 4.7 or 5.2 or whatever ph to breed but find they breed just fine if the 'real' ph is higher as long as the water is very pure.

I also keep reading people telling others you must lower your ph - add leaves or use ph down solution or what-have you which of course will not do much to improve the health of more sensitive fishes.
-
So of course this leaves to two comments which i asked in the first post: Is ph ever actually relevant and would the fish world be better off if ph was never mentioned.

 

[dw1305]

Hi all,

The motivation for this question is new fish keepers are often confused by ph -

They are, and it isn't helped by various charlatans talking about "pH stability" so that they can sell them the World's most expensive sodium bicarbonate (NaHCO3), or some other useless product.

they keep trying to lower the ph without fundamentally changing the water chemistry - and this raises the question if you have good water chemistry does it really matter what the ph actually measures even in advance case.

People like being proactive, and they also like black and white answers in a "shades of grey world". I tell people find fish and plants that are suited the water you have. If you have soft water you can make it harder and more alkaline easily, but if you have hard, alkaline water you can't make it suitable for soft water organisms by adding things to it.

I keep reading that xyz require 4.7 or 5.2 or whatever ph to breed but find they breed just fine if the 'real' ph is higher as long as the water is very pure.

I like some humic substances, and they will reduce pH in low conductivity water.

So of course this leaves to two comments which i asked in the first post: Is ph ever actually relevant and would the fish world be better off if ph was never mentioned.

I think you have to mention pH, it is an important parameter, but intrinsically has a lot of complexity because it is a log10 scale etc.

I think Richard Feynman said that if you can't explain a concept in simple terms? You don't really understand it - <"https://www.tes.com/magazine/teaching-learning/general/what-is-the-feynman-technique">.
I've got better, but my chemistry will never be great, and I struggle with the explanation.

I really like UKAPS members Andy Pierce's web site for water chemistry - <"https://niade.com/category/science/water-chemistry/">.

Cheers Darrel

 

[anewbie]

Hi all,


I think you have to mention pH, it is an important parameter

Cheers Darrel

But this is my question - why is ph an important parameter given tds,kh,gh. ph is a by product of the water chemistry and a given chemistry will reproduce the ph but the ph will not tell you anything about the water chemistry.

If i hand you a jug of water with tds 500 but a ton of co2 to bring the ph to 4.7 what have you learned about the water when you measure the ph. Worse do the fishes care if the ph is 4.7 or 8.2 if the kh/gh composition is from their native environment ?

 

[dw1305]

Hi all,

But this is my question - why is ph an important parameter given tds,kh,gh. ph is a by product of the water chemistry and a given chemistry will reproduce the ph but the ph will not tell you anything about the water chemistry.

It tells you about the relative abundance of acids - "proton donors", and usually that tells you the relative proportion of bases "proton acceptors".

If i hand you a jug of water with tds 500 but a ton of co2 to bring the ph to 4.7 what have you learned about the water when you measure the ph.

This back to the CO2, bicarbonate (HCO3-) and pH equilibrium, pH levels are regulated by the level of atmospheric CO2. When you add CO2 you change the pH equilibrium point. My understanding is that the chemistry of dissolved inorganic carbon is different and doesn't effect alkalinity etc.

Worse do the fishes care if the ph is 4.7 or 8.2 if the kh/gh composition is from their native environment ?

That would really be my point, find organisms that are adapted to the water you can supply, it is a lot better (and easier) for you, and your livestock, in the long run.

Cheers Darrel

 

[neo705]

Hi (again) anewbie,

As an inexperienced apisto keeper I see the recommended pH value and the most I get from it is "this fish likes a slightly acidic water, so maybe I need to avoid seiryu stones and add more botanicals". But this is mainly because the kh needed is very low.
With kh of 0 you can't really measure pH and if you do it's going to he wildly unreliable.

However, there's got to be something in pH that means something. As an example, a chocolate gourami requires more or less the same kh/gh/tds as apistos but much lower pH (4.5 being optimal). So maybe the pH here is the amount of various acids in the water? Because just like above I would "add even more botanicals"

I'm not sure how important it is for apistogramma but I have an example that may or may not help.
Snails in a tank with a certain hardness and tds can be absolutely fine. By injecting co2 and dropping the pH by 1 the snails shells will inevitably erode and the snails will die, all whilst the hardness and TDS remained unchanged. So I think certain species have evolved (with their osmoregulation and other things like slime coat) to be better geared towards certain pH.

Just for transparency, the above is all how I perceive it. I don't ignore pH but it's lower down the priority list compared to hardness. But I also treat tds with the same ambiguity. As in if kh/gh are fine and nitrates are low why does tds matter?

 

[anewbie]

Hi (again) anewbie,

As an inexperienced apisto keeper I see the recommended pH value and the most I get from it is "this fish likes a slightly acidic water, so maybe I need to avoid seiryu stones and add more botanicals". But this is mainly because the kh needed is very low.
With kh of 0 you can't really measure pH and if you do it's going to he wildly unreliable.

However, there's got to be something in pH that means something. As an example, a chocolate gourami requires more or less the same kh/gh/tds as apistos but much lower pH (4.5 being optimal). So maybe the pH here is the amount of various acids in the water? Because just like above I would "add even more botanicals"

I'm not sure how important it is for apistogramma but I have an example that may or may not help.
Snails in a tank with a certain hardness and tds can be absolutely fine. By injecting co2 and dropping the pH by 1 the snails shells will inevitably erode and the snails will die, all whilst the hardness and TDS remained unchanged. So I think certain species have evolved (with their osmoregulation and other things like slime coat) to be better geared towards certain pH.

Just for transparency, the above is all how I perceive it. I don't ignore pH but it's lower down the priority list compared to hardness. But I also treat tds with the same ambiguity. As in if kh/gh are fine and nitrates are low why does tds matter?

But again do chcoolate gourami require much lower ph or is that just what someone measured and was too lazy to check tds/kh/gh ? I've kept and bred fishes that others stay require ph 4.x at somehwere between 5.7 and 6.1 and had no problem breeding them and keeping them alive.

 

[neo705]

But again do chcoolate gourami require much lower ph or is that just what someone measured and was too lazy to check tds/kh/gh ? I've kept and bred fishes that others stay require ph 4.x at somehwere between 5.7 and 6.1 and had no problem breeding them and keeping them alive.

I hope they do as I always wanted some (especially the vaillant's/samurai ones) .but never kept them due to the super low pH

I hope someone has an answer to your question. I'm interested to know too.

 

[anewbie]

I hope they do as I always wanted some (especially the vaillant's/samurai ones) .but never kept them due to the super low pH

I hope someone has an answer to your question. I'm interested to know too.

In truth water that is extremely soft will settle on a low ph. My discus tank claims to have 4.5-4.7 ph and a steady state of 20 ec; though enough decaying matter like leaves will raise the ec. It takes very little to impact ph and/or ec at the low end. Conversely it is very difficult to accurately measure low ph and so my measurement could be in error

 

[Ben Rhau]

The thought with some species of gourami is that replicating low pH will exclude pathogens that can’t survive in that acidity. In nature, these fish don’t see pathogens that are selected at higher pH, so their immune systems may not be able to handle it.

Additionally, some species have only been reported to breed at very low pH. I take that with a grain of salt, since the number of reports is very small and there are many other factors that affect breeding.

That said, I see advanced keepers using higher than reported pH for those species, and their fish seem to be doing fine.

So, I also don’t know if it matters.

In apistos, it has been reported that pH may contribute to male/female ratio in the offspring.

 

[MacZ]

It is just a manner of showing completeness. For some water sources it is more important than others, especially if one is interested in keeping breeding. pH is important for fish from hard water sources like those from rift lakes in Africa compared to softwater species like apistos.

For riftlakecichlids it is more important than for softwater species. From my long experience breeding Malawis and Tanganyikans my conclusion is: You will experience losses if pH drops under 7. Especially with Lake Tanganyika. Hardness is secondary as the rift lakes are not that hard water. You have more room upwards and down for softwater fish in comparison.