My Apistogramma borellii

[MacZ]

Maybe it's because having a true soft water aquarium is not a widespred practice.

Exactly. Many people fear that leap. I know for sure I did. Turns out: The warnings are pretty much BS.

So, if I get this right, Ph fluctuations would result from fluctuations in CO2/O2 levels in the tank, only ?

Scratch the O2. But yes.

So do these types of aquariums do best with little or no aquatic plants, then ? Floaters and immersed plants should be ok because they get their CO2 from the atmosphere.

Emerse plants. But yes. Immersed means "under water". I only keep aquatic plants that can cheat by either floating or having swimming leaves like Nymphaea.

Again, sorry for all these "simple" questions, but I'm new to this and never did all that well in science class (even though I find the subject interesting)...

Don't be sorry. At least you ask the right questions and don't need the full course on that topic. I've met people that lacked the absolute basics of chemistry and physics that were also unable to research those by opening Wikipedia, so I had to start at zero. Helping you out is a walk in the park.

 

[Ben Rhau]

The conventional wisdom on the forums is that, because pure water has "no" buffer, any small amount of ion change will swing the pH and there is nothing to stabilize it. There are a few key reasons this idea isn't relevant for aquariums:

1. Perhaps the easiest way to think about it is that it's still water. A liquid that's pH 2 or pH 12 could be dangerous if it was concentrated enough that you could clean corroded pipes with it. But pure water has a very low number of ions, so even if the pH was far from 7, it would be so dilute as to be harmless.
2. The actual pH of the water, as I've stated several times earlier in this thread, rarely matters to the fish.
3. When exposed to the atmosphere, pure water isn't actually bufferless. This is because the air has some small amount of CO2 that dissolves into the water, which yields both carbonic acid (an acid) and carbonate (a buffer). The resulting water is highly resistant to spontaneous change.

#3 is a little bit more technical, but it's true. I suppose these forum gurus have never actually tried to get the pH of distilled water below 5. It's not easy. You have to add concentrated acid, and more than you might imagine.

The idea of pure water pH "swinging wildly" is one of those things that makes intuitive sense, so it's repeated many times without critical thought or experiment.

 

[MacZ]

You have to add concentrated acid, and more than you might imagine.

Or steady addition of weak acids like humic and tannic acids.

For comparison:
Only using botanicals, elder cone extract and rooibos tea it took me almost 9 months to get the pH down to a (normalized average!) pH of 5.5

 

[Yoannikko]

Exactly. Many people fear that leap. I know for sure I did. Turns out: The warnings are pretty much BS.

Yeah I get it, it's a bit of a scary step for me as well ^^'

Scratch the O2. But yes.

Ah right, thanks !

Emerse plants. But yes. Immersed means "under water". I only keep aquatic plants that can cheat by either floating or having swimming leaves like Nymphaea.

Emersed, that's the one ^^ I like the Nymphae as well, though it might get too big for this tank. I might look into plants like the Nymphoides taiwan, although it's not very accurate as far as the biotope is concerned.

Don't be sorry. At least you ask the right questions and don't need the full course on that topic. I've met people that lacked the absolute basics of chemistry and physics that were also unable to research those by opening Wikipedia, so I had to start at zero. Helping you out is a walk in the park.

Thanks ! I try to do some research on my own as well, as I think it's important to at least have a basic understanding of something before asking questions. Plus, I do like learning about these kinds of things even though I may not fully understant everything at first. But I also enjoy discussing these things with other like-minded people.

The conventional wisdom on the forums is that, because pure water has "no" buffer, any small amount of ion change will swing the pH and there is nothing to stabilize it. There are a few key reasons this idea isn't relevant for aquariums:

1. Perhaps the easiest way to think about it is that it's still water. A liquid that's pH 2 or pH 12 could be dangerous if it was concentrated enough that you could clean corroded pipes with it. But pure water has a very low number of ions, so even if the pH was far from 7, it would be so dilute as to be harmless.
2. The actual pH of the water, as I've stated several times earlier in this thread, rarely matters to the fish.
3. When exposed to the atmosphere, pure water isn't actually bufferless. This is because the air has some small amount of CO2 that dissolves into the water, which yields both carbonic acid (an acid) and carbonate (a buffer). The resulting water is highly resistant to spontaneous change.

#3 is a little bit more technical, but it's true. I suppose these forum gurus have never actually tried to get the pH of distilled water below 5. It's not easy. You have to add concentrated acid, and more than you might imagine.

The idea of pure water pH "swinging wildly" is one of those things that makes intuitive sense, so it's repeated many times without critical thought or experiment.

I've been saying to myself that, as you said, pH doesn't matter all that much, but a little voice in my head keeps telling me to "watch out for those wild swings" because the kH will be too low to do any kind of buffering. But it's more fear of the unknown than anything else ^^

As far as point #3 goes, I've recently read about how water captures CO2 from the atmosphere or expels it from the water to reach a sort of equilibrium. But in order to achieve this, flow and circulation inside the tank have to be optimized so that the CO2 reaches all levels of the aquarium in order to benefit gaseous exchanges. This was in an article about how circulation and flow affects CO2 levels in tanks with CO2 injection. But I guess the principle applies to non-CO3 injected tanks. And this would be even more important to take into accound in a soft water aquarium ? Or am does this have nothing to do with what you're talking about ? ^^'

 

[Ben Rhau]

As far as point #3 goes, I've recently read about how water captures CO2 from the atmosphere or expels it from the water to reach a sort of equilibrium. But in order to achieve this, flow and circulation inside the tank have to be optimized so that the CO2 reaches all levels of the aquarium in order to benefit gaseous exchanges. This was in an article about how circulation and flow affects CO2 levels in tanks with CO2 injection. But I guess the principle applies to non-CO3 injected tanks. And this would be even more important to take into accound in a soft water aquarium ? Or am does this have nothing to do with what you're talking about ? ^^'

The water doesn't "capture" CO2, it happens passively through diffusion. Diffusion is very efficient without the need for flow or forced circulation. Think of what happens when you put a drop of food coloring in water. It very quickly makes its way through the water without needing mechanical agitation. The waterline of your aquarium is open to the air, so it has access to CO2 constantly.

You can do this experiment yourself. Buy a gallon of distilled water and measure the pH. It's probably around pH 5 or 6. It doesn't change much (if at all) from day to day. The amount of dissolved CO2 is not very high, but it's enough to behave as an obvious buffer.

The article you referenced is talking about forcing an amount of dissolved CO2 into the aquarium that's higher than what occurs passively. To do that, you need to continually add a higher concentration of CO2 gas than is present in the air, which you are not doing.

 

[MacZ]

Emersed, that's the one ^^ I like the Nymphae as well, though it might get too big for this tank. I might look into plants like the Nymphoides taiwan, although it's not very accurate as far as the biotope is concerned.

Nymphoides sp. taiwan don't have floating leaves. And a normal Nymphaea works great. You've seen the pictures of my tank. That's a standard Nymphaea lotus (green).

Thanks ! I try to do some research on my own as well, as I think it's important to at least have a basic understanding of something before asking questions. Plus, I do like learning about these kinds of things even though I may not fully understant everything at first. But I also enjoy discussing these things with other like-minded people.

Isn't education a great thing?

You can do this experiment yourself. Buy a gallon of distilled water and measure the pH. It's probably around pH 5 or 6. It doesn't change much (if at all) from day to day. The amount of dissolved CO2 is not very high, but it's enough to behave as an obvious buffer.

Don't forget: If using a pH meter, the sample has to have conductivity raised by adding salt and drip tests are not working correctly if KH is under 2°.

 

[Yoannikko]

The water doesn't "capture" CO2, it happens passively through diffusion. Diffusion is very efficient without the need for flow or forced circulation. Think of what happens when you put a drop of food coloring in water. It very quickly makes its way through the water without needing mechanical agitation. The waterline of your aquarium is open to the air, so it has access to CO2 constantly.

You can do this experiment yourself. Buy a gallon of distilled water and measure the pH. It's probably around pH 5 or 6. It doesn't change much (if at all) from day to day. The amount of dissolved CO2 is not very high, but it's enough to behave as an obvious buffer.

The article you referenced is talking about forcing an amount of dissolved CO2 into the aquarium that's higher than what occurs passively. To do that, you need to continually add a higher concentration of CO2 gas than is present in the air, which you are not doing.

Yeah, I see what you mean. In this instance, there wouldn't really need to be any flow (although there will be) then, just a clean surface so as not to hinder the exchanges of gases.

Nymphoides sp. taiwan don't have floating leaves. And a normal Nymphaea works great. You've seen the pictures of my tank. That's a standard Nymphaea lotus (green).

I was't sure what plant it had, as I was used to seeing red Lotus plants, which get quite big iirc. Yours looks great, I'll keep it mind if I do decide to add some aquatic plants. Still not sure if I'm going to keep the water level where it's at or if I'll raise it. If I don't, I'll try to find some emersed plants that don't get too tall.

Isn't education a great thing?

Haha, to be honest I didn't really think so when I was in school ! ^^' But now that I can pick and choose the topics I want to learn about, I'm coming around

 

[anewbie]

My problem with this is the premise that ph swing is in itself bad. Is it bad? does actual ph matter along as the bacteria colony remains stable? I.e, i realize from Mike comments that the bacteria above 7 is different than below 7 (though 7 might not be a hard number); but does it really have much of an impact on the fishes if in the morning the ph is 6.5 and in the evening it is 4.5 ?

The conventional wisdom on the forums is that, because pure water has "no" buffer, any small amount of ion change will swing the pH and there is nothing to stabilize it. There are a few key reasons this idea isn't relevant for aquariums:

1. Perhaps the easiest way to think about it is that it's still water. A liquid that's pH 2 or pH 12 could be dangerous if it was concentrated enough that you could clean corroded pipes with it. But pure water has a very low number of ions, so even if the pH was far from 7, it would be so dilute as to be harmless.
2. The actual pH of the water, as I've stated several times earlier in this thread, rarely matters to the fish.
3. When exposed to the atmosphere, pure water isn't actually bufferless. This is because the air has some small amount of CO2 that dissolves into the water, which yields both carbonic acid (an acid) and carbonate (a buffer). The resulting water is highly resistant to spontaneous change.

#3 is a little bit more technical, but it's true. I suppose these forum gurus have never actually tried to get the pH of distilled water below 5. It's not easy. You have to add concentrated acid, and more than you might imagine.

The idea of pure water pH "swinging wildly" is one of those things that makes intuitive sense, so it's repeated many times without critical thought or experiment.

 

[dw1305]

Hi all,

My problem with this is the premise that ph swing is in itself bad. Is it bad?

No, not necessarily. In soft water pH is inherently unstable.

If you keep Lake Tanganyika cichlids they have evolved to live in strongly carbonate buffered water where pH will always be above pH7. Once you move away from this scenario pH stability becomes much less important for invertebrates, fish and the microbial community.

Have a look at <"https://www.ukaps.org/forum/threads...nces-university-of-wisconsin—milwaukee.71023/">.

cheers Darrel