Guppies And Their Water: General Hardness And Alkalinity Question

[Bubble.Guppy]

I contacted my local water provider and recieved some information about our local water supply that I use for my fish tank.
 
I attached a small section of what they sent me.
 
Would someone help me understand what these values mean and how they apply to general hardness/alkalinity requirements for my guppy's?
 
 
Thank you!!! 

 

[Byron]

I don't know what the two columns represent, and there are numbers in the first but the second has some numbers or "not tested," so I will just go with the numbers given.  You are most interested in the "Hardness as calcium carbonate" which we call the general hardness.  Akalinity is also important, this is the carbonate hardness usually abbreviated as KH (from the German for carbon, Karbon).
 
The GH represents the minerals dissolved in the water.  This value will not change much if at all in the aquarium, and it does affect all fish.  I can explain this aspect if asked.  There are several measurement scales used for water hardness; the two most common in the hobby are degrees (dGH) and ppm (parts per million).  The latter happens to be identical to mg/l, so your water has a GH of 50-51 ppm.  Just so you know, you can convert ppm to/from dGH with the number 17.9, multiply dGH by 17.9 to get the equivalent ppm, or divide ppm by 17.9 to get the equivalent dGH.  So 50 ppm is about 2.7, or almost 3 dGH.  This is very soft water; I'll come back to this.
 
The alkalinity or KH is important because this serves to buffer the pH, preventing fluctuations.  The KH also adds to the total dissolved solids, and these impact fish, but minimally for our purposes here.  Same scales are used, with the same 17.9 calculation, so your 36-37 ppm is about 2 dKH.  This is low and therefore will have little effect on buffering the pH.  Now that you know the number, I would tend to ignore it.
 
Livebearers, which obviously includes the guppy, come from areas in Central America and Mexico that have moderately hard water.  Most of these need more mineral in the water, and 9-10 dGH is usually considered the absolute minimum generally speaking.  However, the guppy has been inbred for generations, and this has seriously weakened the fish.  It is able to manage with much softer water than any of the other livebearers, or than wild caught fish could survive.  However, it would be better to increase the GH (and corresponding pH).  This is easy to achieve, assuming these are the only fish in the tank; using a sand or fine gravel composed of crushed coral and aragonite will increase GH, KH and pH.  I would not do this if soft water fish are present, however, simply because they will fare much better in your tap water as it is.  And they will have more serious issues with harder water than the guppy will with softer.
 
Hope this helps.  Ask about any bit that isn't clear.
 
Byron.

 

[Bubble.Guppy]

I don't know what the two columns represent, and there are numbers in the first but the second has some numbers or "not tested," so I will just go with the numbers given.  You are most interested in the "Hardness as calcium carbonate" which we call the general hardness.  Akalinity is also important, this is the carbonate hardness usually abbreviated as KH (from the German for carbon, Karbon).
 
The GH represents the minerals dissolved in the water.  This value will not change much if at all in the aquarium, and it does affect all fish.  I can explain this aspect if asked.  There are several measurement scales used for water hardness; the two most common in the hobby are degrees (dGH) and ppm (parts per million).  The latter happens to be identical to mg/l, so your water has a GH of 50-51 ppm.  Just so you know, you can convert ppm to/from dGH with the number 17.9, multiply dGH by 17.9 to get the equivalent ppm, or divide ppm by 17.9 to get the equivalent dGH.  So 50 ppm is about 2.7, or almost 3 dGH.  This is very soft water; I'll come back to this.
 
The alkalinity or KH is important because this serves to buffer the pH, preventing fluctuations.  The KH also adds to the total dissolved solids, and these impact fish, but minimally for our purposes here.  Same scales are used, with the same 17.9 calculation, so your 36-37 ppm is about 2 dKH.  This is low and therefore will have little effect on buffering the pH.  Now that you know the number, I would tend to ignore it.
 
Livebearers, which obviously includes the guppy, come from areas in Central America and Mexico that have moderately hard water.  Most of these need more mineral in the water, and 9-10 dGH is usually considered the absolute minimum generally speaking.  However, the guppy has been inbred for generations, and this has seriously weakened the fish.  It is able to manage with much softer water than any of the other livebearers, or than wild caught fish could survive.  However, it would be better to increase the GH (and corresponding pH).  This is easy to achieve, assuming these are the only fish in the tank; using a sand or fine gravel composed of crushed coral and aragonite will increase GH, KH and pH.  I would not do this if soft water fish are present, however, simply because they will fare much better in your tap water as it is.  And they will have more serious issues with harder water than the guppy will with softer.
 
Hope this helps.  Ask about any bit that isn't clear.
 
Byron.

 
 
Okay great, now I know what the KH comes from, calcium carbonate.
I could mostly find water requirement values for dGH so the formula to get that from ppm is a great thing.
So the dKH is the buffer for ph, and the buffer keeps the pH from fluctuating erratically?
 
I would like to increase my GH and the corresponding pH because I feel my guppys would enjoy their life more. However, I do have a few Juli Cory Cats that are in the tank as well. How would a higher GH affect these species?
 
Also, if I do chhose to increase the GH, how will I know how much to add when it comes to crushed coral or aragonite? I am assuming that it would be hard to achieve a GH that is too high for guppys since they enjoy such a high GH?
I am interested in how the GH general hardness affects fish more specifically, if you could go further into it, that would be great. Then I could make an educated decision on if it would be worth it or not for my setup. I love my guppys more than my Cory's so if needed I could rehome the cory's and get a bottom feeder species better suited to harder water.
 
Thank you so much for your time and knowledge. I am very grateful and it was very informative. THANK YOU!!

 
-Michael

 

[Byron]

You're welcome.  Keep in mind I am not a chemist, so my understanding is gained from my research as part of the hobby, and will be less technical to avoid confusing all of us, including me.
 

Okay great, now I know what the KH comes from, calcium carbonate.
 

 
Not exactly, though they are obviously related.  Calcium carbonate is the GH, which is the dissolved mineral/mineral salts in the water.  KH might be better termed bicarbonate hardness, as it is comprised of the calcium, carbonate, and bicarbonate ions plus the dissolved CO2.  The pH sort of governs the ratio of ions, but the pH is then buffered according to the strengths.  Which leads to your question:
 

So the dKH is the buffer for ph, and the buffer keeps the pH from fluctuating erratically?
 

 
Yes, basically.  When an acid for example is added (as the so-called pH Down chemicals attempt to do, or the aquarist adding organic matter, etc) it may temporarily lower the pH, but the buffering effect of the KH will return the pH to where it was as governed by the ion ratio.  So this in itself creates a fluctuating pH, which is why attempts to adjust the pH should never be undertaken except in conjunction with the GH and KH due to the inter-relationship.  But the natural acidification processes occurring in every aquarium will be impacted by the buffering capability, up to the point when that capacity is reached.  After that, the pH may suddenly lower very rapidly, crashing as we term it.  This is another reason for regular partial water changes, to ensure the water chemistry is maintained in a relatively stable state.  Keeping the filter clean, the substrate clean, and not overloading fish or overfeeding are all things that also factor in to this.
 
 

I would like to increase my GH and the corresponding pH because I feel my guppys would enjoy their life more. However, I do have a few Juli Cory Cats that are in the tank as well. How would a higher GH affect these species?
 
Also, if I do chhose to increase the GH, how will I know how much to add when it comes to crushed coral or aragonite? I am assuming that it would be hard to achieve a GH that is too high for guppys since they enjoy such a high GH?
 

 
Corydoras species are very sensitive to water conditions.  However, not all species are the same.  Those that are being bred commercially will be less bothered, though extremes should be avoided as we cannot change the physiology of a species in so short a period of time.  First, I would ask if you really have Corydoras julii.  What is normally available in stores as this species is not, being C. trilineatus.  Both to the best of my knowledge are still wild caught; C. julii is endemic to one system--the Rio Parnaiba in NE Brazil--that is not commonly fished, so one sees this species infrequently.  How they got mixed up I can't remember, but doesn't matter.  The only relevancy here is that C. julii will be more a bit more fussy than C. trilineatus which has a much larger distribution.
 
However, so long as it is not excessively hard, raising the GH should be possible.  You could aim for somewhere around 8-10 dGH.  To better control this, I would not use a substrate of calcareous rock but place some in a nylon mesh bag in the filter.  It takes a bit of experimenting to get the amount, but start with little and work up, allowing a week between additions for things to settle out.  There are of course commercial preparations, but these over time are expensive, and the quantity of calcareous fine gravel will last years.
 

I am interested in how the GH general hardness affects fish more specifically, if you could go further into it, that would be great. Then I could make an educated decision on if it would be worth it or not for my setup. I love my guppys more than my Cory's so if needed I could rehome the cory's and get a bottom feeder species better suited to harder water.
 

 
The last point first...as mentioned above, I would not worry much in this case, but raise the GH a bit.
 
In general terms, fish are more closely tied to their aquatic environment than any terrestrial animal.  The water literally governs their life.  This is because of the unique physiology of fish.  Fish are directly impacted by GH and TDS [total dissolved solids, of which the GH is one part]; their growth, the transfer of nutrients and waste products through cell membranes, spawning (sperm transfer, egg fertility or hatching), and the proper functioning of internal organs such as the kidneys can all be affected.  Water is constantly entering the fish, through osmosis in every cell, and via the gills.  At this point, I must mention the homeostasis, which has been defined as “the tendency of an organism or a cell to regulate its internal conditions, usually by a system of feedback controls, so as to stabilize health and functioning, regardless of the outside changing conditions.”  Physiological homeostasis, or physical equilibrium, is the internal process animals use to maintain their health and life.  
 
Each species of fish has evolved within a specific environment—and by “environment” in this context we mean everything associated with the water in which the fish lives—and the physiological homeostasis only functions well within that environment.  The water chemistry along with the environmental factors of the habitat are crucial not only to the life of the fish but to the state of its health during that life.  A normal lifespan is virtually impossible if the fish’s environmental needs are not met to some extent.  I'll return to this momentarily, but I mentioned the gills earlier.  Four important body functions of homeostasis are closely associated with processes in the gills: gas exchange, hydromineral (osmoregulation) control, acid-base balance [pH] and nitrogenous waste excretion [ammonia].  These processes are possible because of the close proximity of the blood flowing through the gills to the surrounding water, as well as the differences in the chemical composition of these two fluids (Bartelme, 2004).
 
Studies carried out on the cardinal tetra found that the calcium in the water entering the fish was being removed by the kidneys.  As this occurred, the increasing calcium blocked the tubes, causing death.  There are no external symptoms...the fish just dies.  Experiments showed that the life span of the fish was directly related to the hardness of the water; the harder the water, the shorter the lifespan.  There can be no doubt but that this applies to all soft water fish.  And when it comes to the hard water species, they need this mineral for the proper functioning of the homeostasis.
 
Byron.

 

[Bubble.Guppy]

You're welcome.  Keep in mind I am not a chemist, so my understanding is gained from my research as part of the hobby, and will be less technical to avoid confusing all of us, including me.
 

Okay great, now I know what the KH comes from, calcium carbonate.
 

 
Not exactly, though they are obviously related.  Calcium carbonate is the GH, which is the dissolved mineral/mineral salts in the water.  KH might be better termed bicarbonate hardness, as it is comprised of the calcium, carbonate, and bicarbonate ions plus the dissolved CO2.  The pH sort of governs the ratio of ions, but the pH is then buffered according to the strengths.  Which leads to your question:
 
So the dKH is the buffer for ph, and the buffer keeps the pH from fluctuating erratically?
 

 
Yes, basically.  When an acid for example is added (as the so-called pH Down chemicals attempt to do, or the aquarist adding organic matter, etc) it may temporarily lower the pH, but the buffering effect of the KH will return the pH to where it was as governed by the ion ratio.  So this in itself creates a fluctuating pH, which is why attempts to adjust the pH should never be undertaken except in conjunction with the GH and KH due to the inter-relationship.  But the natural acidification processes occurring in every aquarium will be impacted by the buffering capability, up to the point when that capacity is reached.  After that, the pH may suddenly lower very rapidly, crashing as we term it.  This is another reason for regular partial water changes, to ensure the water chemistry is maintained in a relatively stable state.  Keeping the filter clean, the substrate clean, and not overloading fish or overfeeding are all things that also factor in to this.
 
 

I would like to increase my GH and the corresponding pH because I feel my guppys would enjoy their life more. However, I do have a few Juli Cory Cats that are in the tank as well. How would a higher GH affect these species?
 
Also, if I do chhose to increase the GH, how will I know how much to add when it comes to crushed coral or aragonite? I am assuming that it would be hard to achieve a GH that is too high for guppys since they enjoy such a high GH?
 

 
Corydoras species are very sensitive to water conditions.  However, not all species are the same.  Those that are being bred commercially will be less bothered, though extremes should be avoided as we cannot change the physiology of a species in so short a period of time.  First, I would ask if you really have Corydoras julii.  What is normally available in stores as this species is not, being C. trilineatus.  Both to the best of my knowledge are still wild caught; C. julii is endemic to one system--the Rio Parnaiba in NE Brazil--that is not commonly fished, so one sees this species infrequently.  How they got mixed up I can't remember, but doesn't matter.  The only relevancy here is that C. julii will be more a bit more fussy than C. trilineatus which has a much larger distribution.
 
However, so long as it is not excessively hard, raising the GH should be possible.  You could aim for somewhere around 8-10 dGH.  To better control this, I would not use a substrate of calcareous rock but place some in a nylon mesh bag in the filter.  It takes a bit of experimenting to get the amount, but start with little and work up, allowing a week between additions for things to settle out.  There are of course commercial preparations, but these over time are expensive, and the quantity of calcareous fine gravel will last years.
 

I am interested in how the GH general hardness affects fish more specifically, if you could go further into it, that would be great. Then I could make an educated decision on if it would be worth it or not for my setup. I love my guppys more than my Cory's so if needed I could rehome the cory's and get a bottom feeder species better suited to harder water.
 

 
The last point first...as mentioned above, I would not worry much in this case, but raise the GH a bit.
 
In general terms, fish are more closely tied to their aquatic environment than any terrestrial animal.  The water literally governs their life.  This is because of the unique physiology of fish.  Fish are directly impacted by GH and TDS [total dissolved solids, of which the GH is one part]; their growth, the transfer of nutrients and waste products through cell membranes, spawning (sperm transfer, egg fertility or hatching), and the proper functioning of internal organs such as the kidneys can all be affected.  Water is constantly entering the fish, through osmosis in every cell, and via the gills.  At this point, I must mention the homeostasis, which has been defined as “the tendency of an organism or a cell to regulate its internal conditions, usually by a system of feedback controls, so as to stabilize health and functioning, regardless of the outside changing conditions.”  Physiological homeostasis, or physical equilibrium, is the internal process animals use to maintain their health and life.  
 
Each species of fish has evolved within a specific environment—and by “environment” in this context we mean everything associated with the water in which the fish lives—and the physiological homeostasis only functions well within that environment.  The water chemistry along with the environmental factors of the habitat are crucial not only to the life of the fish but to the state of its health during that life.  A normal lifespan is virtually impossible if the fish’s environmental needs are not met to some extent.  I'll return to this momentarily, but I mentioned the gills earlier.  Four important body functions of homeostasis are closely associated with processes in the gills: gas exchange, hydromineral (osmoregulation) control, acid-base balance [pH] and nitrogenous waste excretion [ammonia].  These processes are possible because of the close proximity of the blood flowing through the gills to the surrounding water, as well as the differences in the chemical composition of these two fluids (Bartelme, 2004).
 
Studies carried out on the cardinal tetra found that the calcium in the water entering the fish was being removed by the kidneys.  As this occurred, the increasing calcium blocked the tubes, causing death.  There are no external symptoms...the fish just dies.  Experiments showed that the life span of the fish was directly related to the hardness of the water; the harder the water, the shorter the lifespan.  There can be no doubt but that this applies to all soft water fish.  And when it comes to the hard water species, they need this mineral for the proper functioning of the homeostasis.
 
Byron.


Byron,
Thank you, now I have a much better understanding of pH, GH, KH, and how they affect each other. Since my water is really soft I think I will invest in some crushed coral or something similar to add to the filter. I surely want to avoid a crash of the pH! Does aquarium salt also raise the GH or KH? I am assuming there is a special test to test the GH? I saw a post somewhere while browsing on how someone used a large jar and added the crushed coral to the water and tested it over a week period to see how much it raised the GH. Does this seem like a plausible test?
 
Unfortunately it seems like I must remove the Cory's that I have. After researching them more, I realized my substrate, which is gravel, can damage their face whiskers and their body since they are a scaleless fish. Not to mention they do not enjoy the same water conditions as the guppy's. My Cory's just do not seem as happy as they could or should be, so I am going to try and pass them on to a fish keeper that already has Cory's so they fit right in.
Anyone in Colorado want a couple Cory's? Free to a good home! 

 
Thank you for breaking down the homeostasis of fish! I have a much better understanding of how and why the water affects the fish so critically!
Byron, you are so very knowledgeable, I really look forward to our future discussions. Thank you for taking the time to teach me! 

 

[Byron]

You are indeed very welcome.  There is much to this hobby, and some aquarists forget (or won't acknowledge) that it is a scientific hobby, in that everything that occurs inside the aquarium is governed solely by science.  We can input into the processes, but must do so very cautiously since the ramifications can be significant.
 

Unfortunately it seems like I must remove the Cory's that I have. After researching them more, I realized my substrate, which is gravel, can damage their face whiskers and their body since they are a scaleless fish. Not to mention they do not enjoy the same water conditions as the guppy's. My Cory's just do not seem as happy as they could or should be, so I am going to try and pass them on to a fish keeper that already has Cory's so they fit right in.
 

 
This is your decision, though again I think they would be OK with moderately hard water.  The substrate is an issue too; I had fine gravel (smooth, not sharp) for years and thought it "OK."  Then on the advice of Heiko Bleher, I changed to play sand.  It does make a difference to the fish.  Corys sift the substrate through their gills in their search for food particles, and while sand causes them no issue, gravel does, to the point they can't really perform this basic function.  I always try to provide fish with what they need or expect, to better ensure good health and "happiness," whatever that word may mean to a fish.
 

Since my water is really soft I think I will invest in some crushed coral or something similar to add to the filter. I surely want to avoid a crash of the pH! Does aquarium salt also raise the GH or KH? I am assuming there is a special test to test the GH? I saw a post somewhere while browsing on how someone used a large jar and added the crushed coral to the water and tested it over a week period to see how much it raised the GH. Does this seem like a plausible test?
 

 
"Salt" as in common salt or aquarium salt is just sodium chloride.  "Salt" as used in marine salt or rift lake cichlid salt is composed of the salts of the hard minerals (calcium, magnesium, etc) and a very different thing; marine salt obviously also contains sodium.  So yes, any salt will raise the GH, but not necessarily provide the mineral salts the fish like livebearers need.  Using calcareous substances is the safest and least expensive method.  Not only will common sodium salt not provide the essential minerals, it is also detrimental to most freshwater fish to some extent.  
 
I've never carried out the jar test, and I would have to doubt its validity.  The hard minerals dissolve slowly into the water, but I am not certain if this occurs at the same rate regardless of the chemistry of the water or not.  I do know that other factors will affect this, so the test in a small container of just water is unlikely to be reliable.  Aquarists do use this to see if the gravel/sand is calcareous or not, that will work; if the GH and pH rises, obvioulsy the material is.  But beyond this, I doubt you can measure it.
 
It does not take much.  I once added half a cup of crushed coral to the filter on my 90g tank, and the pH within a day rose from 6.4 to 7.6; the GH did not budge from near zero.  So one does have to be careful.
 
If you only intend this in one aquarium, and not too large, you might want to look into the commercial buffers.  Just test these out too, as again the individual chemistry in an aquarium can be very different.
 
Byron.