WATER HARDNESS

[Essjay]

I have not personally used an electronic GH device, I suspect it's actually a TDS meter. That's total dissolved solids and it measures everything dissolved in water, not just GH.
GH is a measure of the amount of divalent metal ions. The most abundant are calcium and magnesium but there are tiny amounts of other divalent metals as well. GH cannot measure monovalent metal ions such as sodium, or trivalent metal ions such as aluminium.
TDS measures all metal ions, all non-metal ions eg nitrate, organic chemicals such as fish hormones as so on. TDS is always higher than GH because it measures GH plus everything else.

Having said all that, many members prefer measuring TDS rather than GH as the total amount of 'stuff' in the water affects fish, not just GH alone.



If you decide to stay with a GH tester, the website Seriously Fish lists the GH range for each species listed on there. For the fish you mention -
Neon tetra, Paracheirodon innesi 18 - 215 ppm, or 1 - 12 dH.
Rummy nose tetras - this is more tricky as there are 3 species sold as rummy nose tetra. Two of them need 2 - 15 dH, the third 1 - 12 dH.
Pearl gourami, Trichopodus leerii 2 - 30 dH

​

Rummy noses - I refer you to a page on Seriously Fish. At the bottom of the page in the Notes section, it goes into detail about the three species sold as rummy noses.

Hemigrammus rhodostomus – Rummy-nose tetra (Hemigrammus rhodostomus) — Seriously Fish

www.seriouslyfish.com

 

[plebian]

I'll let Byron present the other side of the coin. Byron was one of our most knowledgeable members who sadly passed away earlier this year. But we still have his wealth of knowledge available on this forum.

Importance of GH over pH in Freshwater Fish Aquaria

In another thread, I was asked by @Uberhoust if I had scientific data to support my frequent advice that GH was the more important parameter when compared to pH [temperature is another critical parameter but outside this particular discussion], and rather than hijack that thread, perhaps start a...

www.fishforums.net

We also have members who have hard water and kept soft water fish. Those who switched to using RO water found their soft water fish lived a lot longer in RO than hard water.

The so called "scientific" evidence reported by Byron is anecdotal, not scientific. The "experiment" made no mention of specific water parameters. Since I've personally kept wild caught cardinal tetras for many years, I seriously doubt water hardness had anything to do with the health issues mentioned in that "study". The health issues were far more likely to have been the result of polluted water from Lake Constance, which had been present for well over one hundred years and was only cleaned up this century.

Your reference to other members experiences is also anecdotal, as is my own experience, which contradicts theirs. I could also mention the experience of long time discus keepers who have reported no health issues whatever while keeping their fish in water they described as "liquid rock". I won't carry the argument any further, other than to mention that relying on RO water is immensely wasteful, and introduces a number of problems of its own if not carefully monitored. IMO, if your water is too hard to keep healthy fish, then you shouldn't be keeping fish.

 

[Marc Pozz]

The so called "scientific" evidence reported by Byron is anecdotal, not scientific. The "experiment" made no mention of specific water parameters. Since I've personally kept wild caught cardinal tetras for many years, I seriously doubt water hardness had anything to do with the health issues mentioned in that "study". The health issues were far more likely to have been the result of polluted water from Lake Constance, which had been present for well over one hundred years and was only cleaned up this century.

Your reference to other members experiences is also anecdotal, as is my own experience, which contradicts theirs. I could also mention the experience of long time discus keepers who have reported no health issues whatever while keeping their fish in water they described as "liquid rock". I won't carry the argument any further, other than to mention that relying on RO water is immensely wasteful, and introduces a number of problems of its own if not carefully monitored. IMO, if your water is too hard to keep healthy fish, then you shouldn't be keeping fish.

Hey your water is your water. fish will live in it as long as things are in balance. We can over do things sometimes. Choose the fish ball park and let it happen. Marc

 

[CaptainBarnicles]

The so called "scientific" evidence reported by Byron is anecdotal, not scientific. The "experiment" made no mention of specific water parameters. Since I've personally kept wild caught cardinal tetras for many years, I seriously doubt water hardness had anything to do with the health issues mentioned in that "study". The health issues were far more likely to have been the result of polluted water from Lake Constance, which had been present for well over one hundred years and was only cleaned up this century.

Your reference to other members experiences is also anecdotal, as is my own experience, which contradicts theirs. I could also mention the experience of long time discus keepers who have reported no health issues whatever while keeping their fish in water they described as "liquid rock". I won't carry the argument any further, other than to mention that relying on RO water is immensely wasteful, and introduces a number of problems of its own if not carefully monitored. IMO, if your water is too hard to keep healthy fish, then you shouldn't be keeping fish.

Why are we still having this argument? There have always been exceptions and people's experiences will differ, obviously, but I think ultimately we have to consider the environments these fish have adapted themselves to live in. There is the argument that most fish are commercially bred and through time and genetics have perhaps adapted to the local water they're being bred in...but that also means that most fish have become weaker and less resilient.

I'm no scientist, but for me personally it just makes logical sense to provide most tropical fish the soft water they're designed to live in. That way we can feel morally confident that we're doing our best to let a fish thrive and not just survive. We wouldn't take a polar bear and force it to live in the Amazon jungle would we? You get the gist of what I'm trying to say.

There are scientific studies that show disease is harder to fight in hard water than in soft water...and if a fish that is adapted to soft water, living in hard water contracts a disease, more than likely said fish will die. You could have the cleanest and most pristine tank on the planet but if another fish brings in diseases from outside you're still going to have a problem.

Now, you can do whatever you want with your fish, in your experience and wisdom you're doing pretty well for yourself and that's great for you. But it's not wasteful to the fish keeper who wants to do their best to provide as natural a system that a glass box can offer to give their fish the best chance at a long and healthy life

 

[Delboy50]

I have not personally used an electronic GH device, I suspect it's actually a TDS meter. That's total dissolved solids and it measures everything dissolved in water, not just GH.
GH is a measure of the amount of divalent metal ions. The most abundant are calcium and magnesium but there are tiny amounts of other divalent metals as well. GH cannot measure monovalent metal ions such as sodium, or trivalent metal ions such as aluminium.
TDS measures all metal ions, all non-metal ions eg nitrate, organic chemicals such as fish hormones as so on. TDS is always higher than GH because it measures GH plus everything else.

Having said all that, many members prefer measuring TDS rather than GH as the total amount of 'stuff' in the water affects fish, not just GH alone.



If you decide to stay with a GH tester, the website Seriously Fish lists the GH range for each species listed on there. For the fish you mention -
Neon tetra, Paracheirodon innesi 18 - 215 ppm, or 1 - 12 dH.
Rummy nose tetras - this is more tricky as there are 3 species sold as rummy nose tetra. Two of them need 2 - 15 dH, the third 1 - 12 dH.
Pearl gourami, Trichopodus leerii 2 - 30 dH

​

Rummy noses - I refer you to a page on Seriously Fish. At the bottom of the page in the Notes section, it goes into detail about the three species sold as rummy noses.

Hemigrammus rhodostomus – Rummy-nose tetra (Hemigrammus rhodostomus) — Seriously Fish

www.seriouslyfish.com

Hi

Yes it is a TDS measure I meant. Well it looks like I can make a start on stocking the tank as my GH is 10 and I plan to keep it that way with the RO & tap water. As I will be doing this on a weekly basis I would like to be able to monitor it quickly so will buy one.

Do I need to add anything minerals into the RO water when mixed with tap water? . The fella mentioned it in the store. The KD is now 3.

Thanks

 

[Essjay]

There are three ways to use RO.

Mix it with tap water. Using this method, there is always some GH in the mixture depending on the ratio of tap:RO used.

Use all RO and add remineralisation salts. This removes just about everything but the remineralisation salts add back some hardness, the level depending on the amount of the salts added. This is sometimes done when there's other things in tap water (eg high nitrate) which the fish keeper wants to remove.

Use all RO and add nothing. This means that GH and KH are zero, or so low we can't measure it. Some fish can live in this but most soft water fish need a bit of hardness.


As you are using a tap + RO mixture, you don't need to add anything else.



KH of 3 is fine as long as you do regular water changes. The natural tendency of a fish tank is to become acidic. KH is a buffer which stops the pH dropping, but it gets used up. When KH is low there is a risk it will all be used up leaving nothing to stop pH falling. If regular water changes are done these top up the KH so it never all get used up.

 

[Delboy50]

There are three ways to use RO.

Mix it with tap water. Using this method, there is always some GH in the mixture depending on the ratio of tap:RO used.

Use all RO and add remineralisation salts. This removes just about everything but the remineralisation salts add back some hardness, the level depending on the amount of the salts added. This is sometimes done when there's other things in tap water (eg high nitrate) which the fish keeper wants to remove.

Use all RO and add nothing. This means that GH and KH are zero, or so low we can't measure it. Some fish can live in this but most soft water fish need a bit of hardness.


As you are using a tap + RO mixture, you don't need to add anything else.



KH of 3 is fine as long as you do regular water changes. The natural tendency of a fish tank is to become acidic. KH is a buffer which stops the pH dropping, but it gets used up. When KH is low there is a risk it will all be used up leaving nothing to stop pH falling. If regular water changes are done these top up the KH so it never all get used up.

 

[Delboy50]

I was thinking of doing 20% per week which equates to about 50 Litres

 

[Essjay]

20 % may not be enough. Though as long as it is every week without fail, it may well be OK.

I started keeping fish before we had broadband and my only source of info was library books. Those were out of date and said water changes were bad, so I did small water changes once every 3 to 4 weeks. That's when I had a couple of pH crashes. Once we had broadband I could research on line, and someone in one forum told me I needed to add remineralisation salts to increase KH. I didn't, because I'd also read about bigger, more frequent water changes and I found that meant I didn't need to add anything. Even so I only increased to 25% water changes so your proposed 20% should be OK as long as it is weekly.

 

[plebian]

There are scientific studies that show disease is harder to fight in hard water than in soft water...

Would love to have a link to your reference, or a copy of the study.

 

[CaptainBarnicles]

Would love to have a link to your reference, or a copy of the study.

Sure thing, here you go

USDA ARS Online Magazine Water Hardness Has Big Role in Fish Disease

For most people, the choice between soft and hard water for everyday use is a matter of preference or geography.

agresearchmag.ars.usda.gov

Like I say, I'm no scientist and you or someone else may poo-poo the above but it's enough for me to make my mind up

 

[plebian]

Sure thing, here you go

USDA ARS Online Magazine Water Hardness Has Big Role in Fish Disease

For most people, the choice between soft and hard water for everyday use is a matter of preference or geography.

agresearchmag.ars.usda.gov

Like I say, I'm no scientist and you or someone else may poo-poo the above but it's enough for me to make my mind up

Thanks for the link. Very interesting, but also a bit mysterious. The first thing to note about that study is that the only subjects were catfish, presumably a single species but that is nowhere specified. The second thing to note is that the only bacteria examined in the study were columnaris. Thirdly, there is no mention of the levels of hardness that were measured. Finally, the study presumable focuses on farmed fish but there is no mention of the size or number of fish involved, total water volume, frequency of water changes, etc. all of which affect bacterial load.

I have a lake bordering my property which contains several species of fish, including catfish, which are regularly caught by the locals. Water hardness measures over 1000 ppm.

As for hobbyist fish for example, African cichlids live in water with a TDS measuring from 125 to 450 ppm dependent on water source, according to Aqueon and other sources. Also, one of the respected European discus farms states the following:

"But from the experience of my customers, who have different water values all over the world and from conversations with professionals from aquaculture, the conductance does not seem to play a major role as long as it is fresh water. Even fish from soft water areas seem to be very adaptable. I heard the most extreme values from Israel, where an acquaintance raised hundreds of thousands of discus fish with conductance values between 800 and 1200 microsiemens and they were very healthy. So before you try to lower your tap water from 550 microsiemens to 200, just leave it at that. It is cheaper, easier and does not run the risk of getting bacteria into the aquarium from contaminated osmosis systems, demineralizers or from activated carbon filters and cartridge filters. This is much more dangerous for the fish than a few hundred microsiemens more."

500 microseimens is equivalent to 320 ppm TDS. You can do the math.

Finally, I have been raising numerous species of Amazonian fish, several wild caught, and have never experienced any bacterial infections whatsoever. The biggest problem in my experience is parasites, not bacteria. Of course all my aquarium are properly filtered, which makes all the difference in the world.

 

[CaptainBarnicles]

Thanks for the link. Very interesting, but also a bit mysterious. The first thing to note about that study is that the only subjects were catfish, presumably a single species but that is nowhere specified. The second thing to note is that the only bacteria examined in the study were columnaris. Thirdly, there is no mention of the levels of hardness that were measured. Finally, the study presumable focuses on farmed fish but there is no mention of the size or number of fish involved, total water volume, frequency of water changes, etc. all of which affect bacterial load.

I have a lake bordering my property which contains several species of fish, including catfish, which are regularly caught by the locals. Water hardness measures over 1000 ppm.

As for hobbyist fish for example, African cichlids live in water with a TDS measuring from 125 to 450 ppm dependent on water source, according to Aqueon and other sources. Also, one of the respected European discus farms states the following:

"But from the experience of my customers, who have different water values all over the world and from conversations with professionals from aquaculture, the conductance does not seem to play a major role as long as it is fresh water. Even fish from soft water areas seem to be very adaptable. I heard the most extreme values from Israel, where an acquaintance raised hundreds of thousands of discus fish with conductance values between 800 and 1200 microsiemens and they were very healthy. So before you try to lower your tap water from 550 microsiemens to 200, just leave it at that. It is cheaper, easier and does not run the risk of getting bacteria into the aquarium from contaminated osmosis systems, demineralizers or from activated carbon filters and cartridge filters. This is much more dangerous for the fish than a few hundred microsiemens more."

500 microseimens is equivalent to 320 ppm TDS. You can do the math.

Finally, I have been raising numerous species of Amazonian fish, several wild caught, and have never experienced any bacterial infections whatsoever. The biggest problem in my experience is parasites, not bacteria. Of course all my aquarium are properly filtered, which makes all the difference in the world.

You do you, matey

 

[noahm]

Thanks for the link. Very interesting, but also a bit mysterious. The first thing to note about that study is that the only subjects were catfish, presumably a single species but that is nowhere specified. The second thing to note is that the only bacteria examined in the study were columnaris. Thirdly, there is no mention of the levels of hardness that were measured. Finally, the study presumable focuses on farmed fish but there is no mention of the size or number of fish involved, total water volume, frequency of water changes, etc. all of which affect bacterial load.

I have a lake bordering my property which contains several species of fish, including catfish, which are regularly caught by the locals. Water hardness measures over 1000 ppm.

As for hobbyist fish for example, African cichlids live in water with a TDS measuring from 125 to 450 ppm dependent on water source, according to Aqueon and other sources. Also, one of the respected European discus farms states the following:

"But from the experience of my customers, who have different water values all over the world and from conversations with professionals from aquaculture, the conductance does not seem to play a major role as long as it is fresh water. Even fish from soft water areas seem to be very adaptable. I heard the most extreme values from Israel, where an acquaintance raised hundreds of thousands of discus fish with conductance values between 800 and 1200 microsiemens and they were very healthy. So before you try to lower your tap water from 550 microsiemens to 200, just leave it at that. It is cheaper, easier and does not run the risk of getting bacteria into the aquarium from contaminated osmosis systems, demineralizers or from activated carbon filters and cartridge filters. This is much more dangerous for the fish than a few hundred microsiemens more."

500 microseimens is equivalent to 320 ppm TDS. You can do the math.

Finally, I have been raising numerous species of Amazonian fish, several wild caught, and have never experienced any bacterial infections whatsoever. The biggest problem in my experience is parasites, not bacteria. Of course all my aquarium are properly filtered, which makes all the difference in the world.

While I have no dog in this fight as far whether the conclusions might be correct or not, as a scientist, I have a special interest in design of experiments. That "study" (at best an experiment) was quite poorly designed. There was zero effort to look at any other factor besides hardness between the two water sources, and in the second experiment, no attempt was made to evaluate filter methods for what they might also filter out or change parameter-wise, and there was no multi-species analysis. Unfortunately it makes their conclusions incredibly speculative even if they might be right. It's like a picture of a blurry UFO...real or not, that evidence is useless.

 

[CaptainBarnicles]

Im not a scientist...


...ooh! Look!