Ph - How Important Is It?

[r.w.girard]

Living in St Louis, water comes out of the tap, according to the city's water report, with a pH between 8.98 and 9.75, an alkalinity between 24-112 [average 57.5] mg/L, a total hardness of 99-160 [average 126] mg/L, and a non-carbonate hardness of 10-143 [average 68] mg/L [source]. Not being a chemist and being new to the hobby, I am not sure which of these correspond to what, but I am under the assumption that KH is alkalinity and GH and non-carbonate hardness. And so, clearly, I need some help.

Now, it would seem to me that the water here is better suited for African cichlids than for South American soft water tetras. But I have a school of green neon tetras in my community tank. As of the moment, I have been trying to keep the pH around 6.4 because, while the green neon tetras thrive in a pH from 4 to 6, I have some fish in the tank that would do best at 7. Therefore, I keep it as low as possible. But doing that is not easy [nor cheap, I suppose]. I am currently using three different Seachem products to maintain what I deem a safe pH: acid buffer [for the KH], acid regulator and neutral regulator [for the pH].

The problem is that, while I have been pretty successful so far - all of my little buddy fishes are swimming around, eating, and looking healthy - I think I might be going about the whole thing wrong. Any advice would be greatly appreciated. But here are a couple of questions:

Can anyone comment about the importance of pH for fish?
Can anyone comment about the relationship between pH and KH [and GH?]?
Can anyone comment on dosing these products per gallon under the above-mentioned water conditions [10 gallon planted tank]?

Experience has shown that the real world does not function like that advice on the back of the bottles...

 

[Bignose]

1) I find pH to be very overstated in its effects. Fish have adapted mechanisms to deal with a wide range of pH. Natural bodies of water don't hold constant pH over time, even as short a time spam as hours. Unless a person is trying to breed, a specific pH is usually not necessary.

Furthermore, the additional of pH uppers or downers via chemicals usually introduces side effects like rampant algae growth into tanks. So, in general, I recommend against those.

2) Unfortunately, the common name here for your fish is a bit confusing. There are a few different fish known as the green neon tetra. There are some that a very closely related to the neon tetra, just a slightly different color variation. These do prefer the softer more acidic water. And I've seen what is more commonly known as the black neon tetra be sold as "green neon tetras" before. The black neon tetra is a relative of the lemon tetra, and actually comes from harder more alkaline waters. So, it would be good to do some research to make sure what you have are the green neon tetra: http/en.wikipedia.org/wiki/Green_neon_tetra

 

[r.w.girard]

1) I find pH to be very overstated in its effects. Fish have adapted mechanisms to deal with a wide range of pH. Natural bodies of water don't hold constant pH over time, even as short a time spam as hours. Unless a person is trying to breed, a specific pH is usually not necessary.

Furthermore, the additional of pH uppers or downers via chemicals usually introduces side effects like rampant algae growth into tanks. So, in general, I recommend against those.

2) Unfortunately, the common name here for your fish is a bit confusing. There are a few different fish known as the green neon tetra. So, it would be good to do some research to make sure what you have are the green neon tetra.

2) Excuse me, I should remember to use scientific names for fish here. They are /Paracheirodon simulans/ and are soft water. Pictures can be found following the link in my signature.

1) I figured as much but I would be worried to keep soft water fish in such hard water and with such a high pH, although I have no intention of breeding them, at least any time soon. As for algae ... that is an entirely different problem I have not started to try and make sense of.

Any comments to that?

 

[bullit]

Ph is not important, its the KH. Relationship wise the Ph will rise when adding KH but there not connected as you could have any levels of hardness to any ph. GH is independent. Baking soda can be used to raise the hardness (teaspoon per 5 gal), aswell as epson salts. If you have a planted tank then this will affect the tank by taking carbonates out the water. To lower the hardness then use peat or RO water. Fish are really looking for the right mineral level, not a specific pH. cheers

 

[Bignose]

Ph is not important, its the KH. Relationship wise the Ph will rise when adding KH but there not connected as you could have any levels of hardness to any ph. GH is independent. Baking soda can be used to raise the hardness (teaspoon per 5 gal), aswell as epson salts. If you have a planted tank then this will affect the tank by taking carbonates out the water. To lower the hardness then use peat or RO water. Fish are really looking for the right mineral level, not a specific pH. cheers

Sort of. Not unlike pH, fish can adapt to wide varieties of hardness, too. Just like pH, hardness is not a constant in most of the freshwater bodies of water in the world. I.e. when it rains, a large amount of water that probably doesn't have the same stats as the original water is mixed -- fish don't die every time it rains.

What is stressful is dramatic changes in hardness. A fish removes its waste using two different principles that sometimes work together, and sometimes work against each other.

A fish removes waste via ion exchange at the gills. That is, when it wants to remove a NH3+ ammonium molecule, it needs to take in some other molecule with a + charge. Potassium K+, or calcium Ca2+ -- which has a +2 charge, so it would remove 2 NH3+ molecules in this case. This maintains the charge balance -- that is, the fish's body remains charge neutral. The second principle is diffusion. Diffusion is the process by which molecules leave an area of high concentration to move to an area of low concentration. Both the concentration of the individual species (like specifically ammonium NH3 or calcium Ca) and the total concentration have an effect on diffusion rates.

When a fish is moved from regions with significantly different amounts of hardness -- different amounts of minerals dissolved in the water -- it causes stress. If moving from high mineral content to lower, there will be less minerals available in the water for ion exchange. The fish's waste will build up in the body some until it adjusts to the new water conditions. If moving from low mineral content to higher, the diffusion gradient will be lesser, or maybe even reversed -- with minerals trying to enter the fish's bodily fluids.

Both of these can be a shock to a fish, and sensitive or weak fish can die from too great of this "hardness shock".

Now, since in most cases, high hardness water is also alkaline, and low hardness is also acidic, this has often been reported as "pH shock". However, my research has uncovered that given the right conditions, a fish can change its internal pH up to 4 pH units an hour. A simple change in pH is nothing to a healthy fish. However, as above, it is the changes in hardness that are the most difficult.

Given a change that is gradual, most healthy fish can adapt to both a pH and a hardness that is far from their native waters. It really depends on the species, however, and this is where research into how sensitive a species is is necessary. And, how a fish has been bred, seems to factor into it as well. Angels and Discus from from very similar water in the Amazon, but angels have been bred in the hard alkaline waters of Florida at commercial aquarium fish farms. Neon tetras, too. Discus however, seem to be more sensitive, and don't do as well and don't seem to breed in those waters. Though, I've seen reports of them not being as sensitive as before.

In short, what really seems to matter is providing reasonably constant conditions. Whatever those conditions are.

 

[r.w.girard]

Given a change that is gradual, most healthy fish can adapt to both a pH and a hardness that is far from their native waters. It really depends on the species, however, and this is where research into how sensitive a species is is necessary. And, how a fish has been bred, seems to factor into it as well. Angels and Discus from from very similar water in the Amazon, but angels have been bred in the hard alkaline waters of Florida at commercial aquarium fish farms. Neon tetras, too. Discus however, seem to be more sensitive, and don't do as well and don't seem to breed in those waters. Though, I've seen reports of them not being as sensitive as before.

In short, what really seems to matter is providing reasonably constant conditions. Whatever those conditions are.

Great information! Thank you!

At the same time, I wonder about this last section, quoted above. I believe that my fish were wild-caught, although there is no way for me to be sure of it. Would that significantly change anything? It seems from what you are saying that it might.

 

[bullit]

I have wildcaught fish in a lower ph but my waters hardness is good at 200mg/l for both k/H and G/H so i leave everything at it is. Agree with bignose on the ph shock that it is the changes in hardness that can affect fish.
cheers

 

[Bignose]

Given a change that is gradual, most healthy fish can adapt to both a pH and a hardness that is far from their native waters. It really depends on the species, however, and this is where research into how sensitive a species is is necessary. And, how a fish has been bred, seems to factor into it as well. Angels and Discus from from very similar water in the Amazon, but angels have been bred in the hard alkaline waters of Florida at commercial aquarium fish farms. Neon tetras, too. Discus however, seem to be more sensitive, and don't do as well and don't seem to breed in those waters. Though, I've seen reports of them not being as sensitive as before.

In short, what really seems to matter is providing reasonably constant conditions. Whatever those conditions are.

Great information! Thank you!

At the same time, I wonder about this last section, quoted above. I believe that my fish were wild-caught, although there is no way for me to be sure of it. Would that significantly change anything? It seems from what you are saying that it might.

Maybe is the best answer that I can give. Perhaps seek someone out who has kept these fish before and ask about their experience. You can ask the LFS where you bought them if they are wild caught or not, too. But, as above, some species can adapt fine, some more sensitive. I haven't kept neon tetras, green or regular, so I really don't know.

 

[r.w.girard]

Well, thank you so much for you advice, commentary, etc&. It is all very much appreciated.