i need help hard/soft water
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there's two types of hardness: GH and KH. GH is a measure of the calcium and magnesium in your water and KH is a measure of the carbonate level. test kits you can only the presence of Ca and Mg but there may be many more cationic species in your water than you're not able to test for. Sodium, Potassium, Titanium, Nickel, Aluminium, Manganese, Copper, Tin are but a few you may have heard of. the sum total of all of them is your total dissolved solids (TDS) and it is THIS function that has the most significant impact on fish ... much more so than Ca and Mg alone. these cations are attached to anion species such as carbonate but may also be silicate, phosphate, sulphate, chloride and others. again, while you're measuring carbonate as KH there are other disolved inorganic compounds in your water that you're not testing for.
when you run water through a home water softener, the anions Ca++ and Mg++ are exchanged for sodium (Na+) but notice the difference in electron charge ... Calcium is a divalent anion (++) but sodium is monovalent (+). this means that when the calcium is exchanged, TWO sodiums must replace ONE calcium or magnesium. the net effect is that while you are softening your water with respect to your laundry and those white spots on your faucet, you are actually INCREASING the total dissolved solids of your water.
fish don't do laundry and thus they are more affected by the TDS of your water than they are with which particular anion it contains.
soft water has little calcium, magnesium or much in the way of total dissolved solids. essentially, the softer the water the more mineral free it is.
the kH of your water is another way to express its buffering capacity. Buffering capacity refers to water's ability to keep the pH stable as acids or bases are added indirectly. bicarbonate (HCO3-), carbonate (CO3-), and in rare instances, hydroxide (OH-) ions are called buffers.
pH and buffering capacity are interrelated with one another; although one might think that adding equal volumes of an acid and neutral water would result in a pH halfway in between, this rarely happens in practice. If the water has sufficient buffering capacity, the buffering capacity can absorb and neutralize the added acid without significantly changing the pH.
think of a buffer as a large sponge. as more acid is added, the "sponge" absorbs the acid without changing the pH much. the "sponge's" capacity is limited however; once the buffering capacity is used up, the pH changes more rapidly as acids are added.
Buffering has both positive and negative consequences. on the plus side, the nitrogen cycle produces nitric acid (nitrate). without buffering, your tank's pH would drop over time not a good thing). with sufficient buffering, the pH stays stable (a good thing). too, free carbon dioxide can form carbonic acid that may potentially decrease the pH level.
on the negative side, hard tap water often almost always has a large buffering capacity. if the pH of the water is too high for your fish, the buffering capacity makes it difficult to lower the pH to a more appropriate value. attempts to change the pH of water usually fail because buffering effects are not taken into account.
in freshwater aquariums, most of water's buffering capacity is due to carbonates and bicarbonates. thus, the terms "carbonate hardness" (KH), "alkalinity" and "buffering capacity" are used interchangeably. although technically not the same things, they are equivalent in practice in the context of fishkeeping. Note: the term "alkalinity" should not be confused with the term "alkaline".
alkalinity refers to buffering, while alkaline refers to a solution that is a base, i.e. pH greater than 7.
How much buffering does your tank need? most aquarium buffering capacity test kits actually measure KH. the larger the KH, the more resistant to pH changes your water will be. a tank's KH should be high enough to prevent large pH swings in your tank over time. If your KH is below roughly 4.5 dH, you should pay special attention to your tank's pH (e.g, test weekly, until you get a feel for how stable the pH is). this is particularly important if you neglect to do frequent partial water changes. why? the nitrogen cycle creates a tendency for an established tank's pH to decrease over time. the exact amount of pH change depends on the quantity and rate of nitrates produced, as well as the KH. if your pH drops more than roughly two tenths of a point (0.2) over a month, you should consider increasing the KH or performing partial water changes more frequently. KH doesn't affect fish directly, so there is no need to match fish species to a particular KH.
Carbonate hardness or temporary hardness. Measures the buffering capacity or the ability to absorb and neutralize added acid without major changes to pH. Think of buffering capacity as a big sponge, the higher the buffering, the bigger the sponge. How much buffering does your tank need? The higher the kH (the bigger the sponge), the more resistant to pH changes your water will be. A tank's kH should be high enough to prevent large pH swings over time. If your kH is below roughly 4.5 OdH, you should pay special attention to your tank's pH (e.g., testing periodically) until you get a feel for how stable the pH is.
Buffering is both good and bad. On the good side, the nitrogen cycle in our tanks produces nitric acid (nitrate). If we don’t have buffering (kH), the pH will drop over time. Sufficient buffering will keep the Ph stable. On the bad side, hard water almost always has a large buffering capacity and if the pH is to high for your fish, this large buffering capacity will make it more difficult to lower the pH.
Buffering is sometimes referred to as "alkalinity" but should not be confused with "alkaline". Alkalinity refers to buffering and alkaline refers to a solution that is base rather than acid (pH).
Aquariums with a low kH will require more attention to water changes to control the nitrate level reducing the tendency for the pH to drop.
Alkalinity is the concentration of bases dissolved in water and expressed as parts per million (ppm) or milligrams per litre (mg/L) Calcium carbonate (CaCO3). These bases are usually bicarbonates (HCO3-) and carbonates (CO3-), and, in rare instances, hydroxide (OH-) ions. These ions, called buffers, are important because they slow the rate at which the pH changes. The magnitude of change is determined by the water's buffering capacity or its ability to absorb acids and/or alkalis (base) and is an often overlooked, though extremely important component of pH balance in an aquarium.
Without a buffering system, free carbon dioxide will form large amounts of carbonic acid that may potentially decrease the nighttime pH level to 4.5. In aquariums where plants are non-existent, a good buffering capacity can prevent excessive build-ups of carbon dioxide and lethal changes in pH. In planted aquariums better growth rates are attained in high alkalinity waters because phosphorus and other essential nutrients become more available to the plants.
Alkalinity is not the same as hardness. Calcium (Ca++) and Magnesium (Mg++) are primarily responsible for hardness. However, in most waters, alkalinity and hardness have similar values because the carbonates and bicarbonates responsible for total alkalinity are usually in the form of Calcium carbonate or Magnesium carbonate. However, waters with high total alkalinity are not always hard, since the carbonates can be in the form of Sodium or Potassium carbonate.
The equation below shows that carbonic acid (H2CO3) dissociates into hydrogen (H+) and bicarbonate (HCO3-) ions. The bicarbonate ions can further dissociate into hydrogen (H+) and carbonate (CO3-) ions. When acid (H+) is introduced into well-buffered water, carbonate ions react with the hydrogen ions to produce bicarbonate. Thus, although acid is added, no change in the overall pH occurs. Furthermore, bicarbonate ions act as an additional reservoir for hydrogen ions. The reactions outlined in the equation below are pH sensitive and shift to the right as pH increases.
H2O + CO2 <=> H2CO3 <=> H+ HCO3- <=> 2H+ + CO3
water + carbon dioxide <=> carbonic acid <=> hydrogen ion + bicarbonate <=> hydrogen + carbonate
The units used to measure alkalinity will depend on the test kit. Some use milliequivalents (meq/L), dKH (German Degrees), mg/L or parts per million (ppm). Meq/L stands for milliequivalents per litre. A milliequivalent is 0.001 of an Equivalent, which is the weight of substance that will react with one atomic weight of hydrogen.
For aquarium purposes, you can use the following conversion factors:
50 ppm (mg/L) = 1 meq/L = 2.8 dKH.
when you run water through a home water softener, the anions Ca++ and Mg++ are exchanged for sodium (Na+) but notice the difference in electron charge ... Calcium is a divalent anion (++) but sodium is monovalent (+). this means that when the calcium is exchanged, TWO sodiums must replace ONE calcium or magnesium. the net effect is that while you are softening your water with respect to your laundry and those white spots on your faucet, you are actually INCREASING the total dissolved solids of your water.
fish don't do laundry and thus they are more affected by the TDS of your water than they are with which particular anion it contains.
soft water has little calcium, magnesium or much in the way of total dissolved solids. essentially, the softer the water the more mineral free it is.
the kH of your water is another way to express its buffering capacity. Buffering capacity refers to water's ability to keep the pH stable as acids or bases are added indirectly. bicarbonate (HCO3-), carbonate (CO3-), and in rare instances, hydroxide (OH-) ions are called buffers.
pH and buffering capacity are interrelated with one another; although one might think that adding equal volumes of an acid and neutral water would result in a pH halfway in between, this rarely happens in practice. If the water has sufficient buffering capacity, the buffering capacity can absorb and neutralize the added acid without significantly changing the pH.
think of a buffer as a large sponge. as more acid is added, the "sponge" absorbs the acid without changing the pH much. the "sponge's" capacity is limited however; once the buffering capacity is used up, the pH changes more rapidly as acids are added.
Buffering has both positive and negative consequences. on the plus side, the nitrogen cycle produces nitric acid (nitrate). without buffering, your tank's pH would drop over time not a good thing). with sufficient buffering, the pH stays stable (a good thing). too, free carbon dioxide can form carbonic acid that may potentially decrease the pH level.
on the negative side, hard tap water often almost always has a large buffering capacity. if the pH of the water is too high for your fish, the buffering capacity makes it difficult to lower the pH to a more appropriate value. attempts to change the pH of water usually fail because buffering effects are not taken into account.
in freshwater aquariums, most of water's buffering capacity is due to carbonates and bicarbonates. thus, the terms "carbonate hardness" (KH), "alkalinity" and "buffering capacity" are used interchangeably. although technically not the same things, they are equivalent in practice in the context of fishkeeping. Note: the term "alkalinity" should not be confused with the term "alkaline".
alkalinity refers to buffering, while alkaline refers to a solution that is a base, i.e. pH greater than 7.
How much buffering does your tank need? most aquarium buffering capacity test kits actually measure KH. the larger the KH, the more resistant to pH changes your water will be. a tank's KH should be high enough to prevent large pH swings in your tank over time. If your KH is below roughly 4.5 dH, you should pay special attention to your tank's pH (e.g, test weekly, until you get a feel for how stable the pH is). this is particularly important if you neglect to do frequent partial water changes. why? the nitrogen cycle creates a tendency for an established tank's pH to decrease over time. the exact amount of pH change depends on the quantity and rate of nitrates produced, as well as the KH. if your pH drops more than roughly two tenths of a point (0.2) over a month, you should consider increasing the KH or performing partial water changes more frequently. KH doesn't affect fish directly, so there is no need to match fish species to a particular KH.
Carbonate hardness or temporary hardness. Measures the buffering capacity or the ability to absorb and neutralize added acid without major changes to pH. Think of buffering capacity as a big sponge, the higher the buffering, the bigger the sponge. How much buffering does your tank need? The higher the kH (the bigger the sponge), the more resistant to pH changes your water will be. A tank's kH should be high enough to prevent large pH swings over time. If your kH is below roughly 4.5 OdH, you should pay special attention to your tank's pH (e.g., testing periodically) until you get a feel for how stable the pH is.
Buffering is both good and bad. On the good side, the nitrogen cycle in our tanks produces nitric acid (nitrate). If we don’t have buffering (kH), the pH will drop over time. Sufficient buffering will keep the Ph stable. On the bad side, hard water almost always has a large buffering capacity and if the pH is to high for your fish, this large buffering capacity will make it more difficult to lower the pH.
Buffering is sometimes referred to as "alkalinity" but should not be confused with "alkaline". Alkalinity refers to buffering and alkaline refers to a solution that is base rather than acid (pH).
Aquariums with a low kH will require more attention to water changes to control the nitrate level reducing the tendency for the pH to drop.
Alkalinity is the concentration of bases dissolved in water and expressed as parts per million (ppm) or milligrams per litre (mg/L) Calcium carbonate (CaCO3). These bases are usually bicarbonates (HCO3-) and carbonates (CO3-), and, in rare instances, hydroxide (OH-) ions. These ions, called buffers, are important because they slow the rate at which the pH changes. The magnitude of change is determined by the water's buffering capacity or its ability to absorb acids and/or alkalis (base) and is an often overlooked, though extremely important component of pH balance in an aquarium.
Without a buffering system, free carbon dioxide will form large amounts of carbonic acid that may potentially decrease the nighttime pH level to 4.5. In aquariums where plants are non-existent, a good buffering capacity can prevent excessive build-ups of carbon dioxide and lethal changes in pH. In planted aquariums better growth rates are attained in high alkalinity waters because phosphorus and other essential nutrients become more available to the plants.
Alkalinity is not the same as hardness. Calcium (Ca++) and Magnesium (Mg++) are primarily responsible for hardness. However, in most waters, alkalinity and hardness have similar values because the carbonates and bicarbonates responsible for total alkalinity are usually in the form of Calcium carbonate or Magnesium carbonate. However, waters with high total alkalinity are not always hard, since the carbonates can be in the form of Sodium or Potassium carbonate.
The equation below shows that carbonic acid (H2CO3) dissociates into hydrogen (H+) and bicarbonate (HCO3-) ions. The bicarbonate ions can further dissociate into hydrogen (H+) and carbonate (CO3-) ions. When acid (H+) is introduced into well-buffered water, carbonate ions react with the hydrogen ions to produce bicarbonate. Thus, although acid is added, no change in the overall pH occurs. Furthermore, bicarbonate ions act as an additional reservoir for hydrogen ions. The reactions outlined in the equation below are pH sensitive and shift to the right as pH increases.
H2O + CO2 <=> H2CO3 <=> H+ HCO3- <=> 2H+ + CO3
water + carbon dioxide <=> carbonic acid <=> hydrogen ion + bicarbonate <=> hydrogen + carbonate
The units used to measure alkalinity will depend on the test kit. Some use milliequivalents (meq/L), dKH (German Degrees), mg/L or parts per million (ppm). Meq/L stands for milliequivalents per litre. A milliequivalent is 0.001 of an Equivalent, which is the weight of substance that will react with one atomic weight of hydrogen.
For aquarium purposes, you can use the following conversion factors:
50 ppm (mg/L) = 1 meq/L = 2.8 dKH.
Hope that was on a file somewhere on your hard drive and you didn't spend the time typing it out just for this post!
Hehe...the key thing to know Fish_O is, for the vast majority of fish, they can adapt to a wide range of water hardness....it is relatively easy to make water harder, a little tougher to soften it up...some fish need it tweaked if you want them to breed...It really all depends on the specific needs of the species you plan to keep and how out of whack your water is compared to those needs...
OFF TOPIC:
Liv, your post looks like an article. I envy people with that much of information in their heads. :bowing:
Liv, your post looks like an article. I envy people with that much of information in their heads. :bowing: