Water

[SeedlessOne]

Ok so i know RO water is good...but it is a pain to keep buying that at the store...so is a brita filter ok to use?? I know it wont be RO water but it sure would be alot easier to get water from my faucet..ya know? So how much better is RO water vs. filered tap?? Enough difference to keep getting RO?:rasta:

SeedlessOne Reviewed by SeedlessOne on 05-11-2006. Water Ok so i know RO water is good...but it is a pain to keep buying that at the store...so is a brita filter ok to use?? I know it wont be RO water but it sure would be alot easier to get water from my faucet..ya know? So how much better is RO water vs. filered tap?? Enough difference to keep getting RO?:rasta: Rating: 5

[Sinsemilla Jones]

http://faq.thekrib.com/begin-chem.html

What You Need to Know About Water Chemistry, and Why

Water in nature is rarely pure in the "distilled water'' sense; it contains dissolved salts, buffers, nutrients, etc., with exact concentrations dependent on local conditions. Fish (and plants) have evolved over millions of years to the specific water conditions in their native habitats and may be unable to survive in significantly different environments.

Beginners (especially the lazy) should take the easy approach of selecting fish whose needs match the qualities of their normal tap water. Alternatively, an advanced (and energetic!) aquarist can change the water characteristics to match the fish's needs, though doing so is almost always more difficult than first appears. In either case, you need to know enough about water chemistry to ensure that the water in your tank has the right properties for the fish you are keeping.

Water has four measurable properties that are commonly used to characterize its chemistry. They are pH, buffering capacity, general hardness and salinity. In addition, there are several nutrients and trace elements.

pH
pH refers to water being either an acid, base, or neither (neutral). A pH of 7 is said to be neutral, a pH below 7 is ``acidic'' and a pH above 7 is ``basic'' or ``alkaline''. Like the Richter scale used to measure earthquakes, the pH scale is logarithmic. A pH of 5.5 is 10 times more acidic than water at a pH of 6.5. Thus, changing the pH by a small amount (suddenly) is more of a chemical change (and more stressful to fish!) than might first appear.

To a fishkeeper, two aspects of pH are important. First, rapid changes in pH are stressful to fish and should be avoided. Changing the pH by more than .3 units per day is known to stress fish. Thus, you want the pH of your tank to remain constant and stable over the long haul. Second, fish have adapted to thrive in a (sometimes narrow) pH range. You want to be sure that your tank's pH matches the specific requirements of the fish you are keeping.

Most fish can adjust to a pH somewhat outside of their optimal range. If your water's pH is naturally within the range of 6.5 to 7.5, you will be able to keep most species of fish without any problems. If your pH lies within this range, there is probably no need to adjust it upward or downward.
Buffering Capacity (KH, Alkalinity)
Buffering capacity refers to water's ability to keep the pH stable as acids or bases are added. pH and buffering capacity are intertwined 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. Conceptually, a buffer acts somewhat like 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 (a bad thing). With sufficient buffering, the pH stays stable (a good thing). 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. Naive attempts to change the pH of water usually fail because buffering effects are ignored.

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 > 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 ESPECIALLY important if you neglect to do frequent partial water changes. In particular, 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 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.

Note: it is not a good idea to use distilled water in your tank. By definition, distilled water has essentially no KH. That means that adding even a little bit of acid will change the pH significantly (stressing fish). Because of its instability, distilled (or any essentially pure water) is never used directly. Tap water or other salts must first be added to it in order to increase its GH and KH.
General Hardness (GH)
General hardness (GH) refers to the dissolved concentration of magnesium and calcium ions. When fish are said to prefer ``soft'' or ``hard'' water, it is GH (not KH) that is being referred to.

Note: GH, KH and pH form the Bermuda's Triangle of water chemistry. Although the three properties are distinct, they all interact with each other to varying degrees, making it difficult to adjust one without impacting the other. That is one reason why beginning aquarists are advised NOT to tamper with these parameters unless absolutely necessary. As an example, ``hard'' water frequently often comes from limestone aquifers. Limestone contains calcium carbonate, which when dissolved in water increases both the GH (from calcium) and KH (from carbonate) components. Increasing the KH component also usually increases pH as well. Conceptually, the KH acts as a ``sponge'' absorbing the acid present in the water, raising the water's pH.

Water hardness follows the following guidelines. The unit dH means ``degree hardness'', while ppm means ``parts per million'', which is roughly equivalent to mg/L in water. 1 unit dH equals 17.8 ppm CaCO3. Most test kits give the hardness in units of CaCO3; this means the hardness is equivalent to that much CaCO3 in water but does not mean it actually came from CaCO3.

General Hardness
0 - 4 dH, 0 - 70 ppm : very soft
4 - 8 dH, 70 - 140 ppm : soft
8 - 12 dH, 140 - 210 ppm : medium hard
12 - 18 dH, 210 - 320 ppm : fairly hard
18 - 30 dH, 320 - 530 ppm : hard
higher : liquid rock (Lake Malawi and Los Angeles, CA)

Salinity
Salinity refers to the total amount of dissolved substances. Salinity measurements count both GH and KH components as well as such other substances as sodium. Knowing water's salinity becomes important in salt water aquariums. In freshwater tanks, knowing pH, GH and KH suffices.

Salinity is usually expressed in terms of its specific gravity, the ratio of a solution's weight to weight of an equal volume of distilled water. Because water expands when heated (changing its density), a common reference temperature of 59F degrees is used. Salinity is measured with a hydrometer, which is calibrated for use at a specific temperature (e.g., 75F degrees is common).

One component of salinity that neither GH or KH includes is sodium. Some freshwater fish tolerate (or even prefer) a small amount of salt (it stimulates slime coat growth). Moreover, parasites (e.g., ick) do not tolerate salt at all. Thus, salt in concentrations of (up to) 1 tablespoon per 5 gallons can actually help prevent and cure ick and other parasitic infections.

On the other hand, some species of fish do not tolerate ANY salt well. Scaleless fish (in general) and some Corydoras catfish are far more sensitive to salt than most freshwater fish. Add salt only if you are certain that all of your tank's inhabitants prefer it or can at least tolerate it.
Nutrients and Trace Elements
In addition to GH, KH, pH and salinity, there are a few other substances you may want to know about. Most tap water contains an assortment of nutrients and trace elements in very low concentrations. The presence (or absence) of trace elements can be important in some situations, specifically:

* nitrates, which are discussed in great length in this FAQ in conjunction with the NITROGEN CYCLE;
* phosphates, the second most prominent nutrient. Phosphates have been linked to algae growth. If you have persistent algae problems, high phosphates may be a contributing factor. In a plant tank, ideal phosphate levels are .2 mg/L or lower. To control algae, frequent partial water changes are often recommended to reduce nutrient levels. If your tap water contains excess phosphate, water changes may be aggravating the situation. Your local water company can tell you what the exact phosphate levels are.
* iron, manganese and other trace elements. Plants need iron in trace quantities to grow. Tap water in many areas contains no iron at all. Consult the PLANT FAQ for more details.

Altering Your Water's Chemistry
Hardening Your Water (Raising GH and/or KH)
The following measurements are approximate; use a test kit to verify you've achieved the intended results. Note that if your water is extremely soft to begin with (1 degree KH or less), you may get a drastic change in pH as the buffer is added.

To raise both GH and KH simultaneously, add calcium carbonate (CaCO3). 1/2 teaspoon per 100 liters of water will increase both the KH and GH by about 1-2 dH. Alternatively, add some sea shells, coral, limestone, marble chips, etc. to your filter.

To raise the KH without raising the GH, add sodium bicarbonate (NaHCO3), commonly known as baking soda. 1/2 teaspoon per 100 Liters raises the KH by about 1 dH. Sodium bicarbonate drives the pH towards an equilibrium value of 8.2.
Raising and Lowering pH
One can raise or lower pH by adding chemicals. Because of buffering, however, the process is difficult to get right. Increasing or decreasing the pH (in a stable way) actually involves changing the KH. The most common approach is to add a buffer (in the previous section) whose equilibrium holds the pH at the desired value.

Muriatic (hydrochloric) acid can be used to reduce pH. Note that the exact quantity needed depends on the water's buffering capacity. In effect, you add enough acid to use up all the buffering capacity. Once this has been done, decreasing the pH is easy. However, it should be noted that the resultant lower-pH water has much less KH buffering than it did before, making it more susceptible to pH swings when (for instance) nitrate levels rise. Warning: It goes without saying that acids are VERY dangerous! Do not use this approach unless you know what you are doing, and you should treat the water BEFORE adding it to the aquarium.

Products such as ``pH-Down'' are often based on a phosphoric acid buffer. Phosphoric acid tends to keep the pH at roughly 6.5, depending on how much you use. Unfortunately, use of phosphoric acid has the BIG side effect of raising the phosphate level in your tank, stimulating algae growth. It is difficult to control algae growth in a tank with elevated phosphate levels. The only advantage over hydrochloric acid is that pH will be somewhat better buffered at its lower value.

One safe way to lower pH WITHOUT adjusting KH is to bubble CO2 (carbon dioxide) through the tank. The CO2 dissolves in water, and some of it forms carbonic acid. The formation of acid lowers the pH. Of course, in order for this approach to be practical, a steady source of CO2 bubbles (e.g. a CO2 tank) is needed to hold the pH in place. As soon as the CO2 is gone, the pH bounces back to its previous value. The high cost of a CO2 injection system precludes its use as a pH lowering technique in most aquariums (though see the PLANT FAQ for inexpensive do-it-yourself alternatives). CO2 injection systems are highly popular in heavily-planted tanks, because the additional CO2 stimulates plant growth.
Softening Your Water (i.e., lowering GH)
Some fish (e.g., discus, cardinal tetras, etc.) prefer soft water. Although they can survive in harder water, they are unlikely to breed in it. Thus, you may feel compelled to soften your water despite the hassle involved in doing so.

Typical home water softeners soften water using a technique known as ``ion exchange''. That is, they remove calcium and magnesium ions by replacing them with sodium ions. Although this does technically make water softer, most fish won't notice the difference. That is, fish that prefer soft water don't like sodium either, and for them such water softeners don't help at all. Thus, home water softeners are not an appropriate way to soften water for aquarium use.

Fish stores also market ``water softening pillows''. They use the same ion-exchange principle. One ``recharges'' the pillow by soaking it in a salt water solution, then places it in the tank where the sodium ions are released into the water and replaced by calcium and magnesium ions. After a few hours or days, the pillow (along with the calcium and magnesium) are removed, and the pillow recharged. The pillows sold in stores are too small to work well in practice, and shouldn't be used for the same reason cited above.

Peat moss softens water and reduces its hardness (GH). The most effective way to soften water via peat is to aerate water for 1-2 weeks in a bucket containing peat moss. For example, get a (plastic) bucket of the appropriate size. Then, get a large quantity of peat (a gallon or more), boil it (so that it sinks), stuff it in a pillow case, and place it in the water bucket. Use an air pump to aerate it. In 1-2 weeks, the water will be softer and more acidic. Use this aged water when making partial water changes on your tank.

Peat can be bought at pet shops, but it is expensive. It is much more cost-effective to buy it in bulk at a local gardening shop. Read labels carefully! You don't want to use peat containing fertilizers or other additives.

Although some folks place peat in the filters of their tanks, the technique has a number of drawbacks. First, peat clogs easily, so adding peat isn't always effective. Second, peat can be messy and may cloud the water in your tank. Third, the exact quantity of peat needed to effectively soften your water is difficult to estimate. Using the wrong amount results in the wrong water chemistry. Finally, when doing water changes, your tank's chemistry changes when new water is added (it has the wrong properties). Over the next few days, the chemistry changes as the peat takes effect. Using aged water helps ensure that the chemistry of your tank doesn't fluctuate while doing water changes.

Hard water can also be softened by diluting it with distilled water or R/O water. R/O (reverse-osmosis) water is purified water made by a R/O unit. Unfortunately, R/O units are too expensive ($100-$500) for most hobbyists. R/O water can also be purchased at some fish stores, but for most folks the expense and hassle are not worth it. The same applies to distilled water purchased at grocery stores.

imp:

http://ga.water.usgs.gov/edu/characteristics.html

The U.S. Geological Survey has been measuring water for decades. Millions of measurements and analyses have been made. Some measurements are taken almost every time water is sampled and investigated, no matter where in the U.S. the water is being studied. Even these simple measurements can sometimes reveal something important about the water and the environment around it. The results of a single measurement of a water's properties are actually less important than looking at how the properties vary over time. For example, if you take the pH of the creek behind your school and find that it is 5.5, you might say "Wow, this water is acidic!" But, a pH of 5.5 might be "normal" for that creek. It is similar to how my normal body temperature (when I'm not sick) is about 97.5 degrees, but my third-grader's normal temperature is "really normal" -- right on the 98.6 mark. As with our temperatures, if the pH of your creek begins to change, then you might suspect that something is going on somewhere that is affecting the water, and possibly, the water quality. So, often, the changes in water measurements are more important than the actual measured values.
pH is only one measurement of a water body's health; there are others, too.

Water temperature
Water temperature is not only important to swimmers and fisherman, but also to industries and even fish and algae. A lot of water is used for cooling purposes in power plants that generate electricity. They need cool water to start with, and they generally release warmer water back to the environment. The temperature of the released water can affect downstream habitats. Temperature also can affect the ability of water to hold oxygen as well as the ability of organisms to resist certain pollutants.

pH
pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water. Water that has more free hydrogen ions is acidic, whereas water that has more free hydroxyl ions is basic. Since pH can be affected by chemicals in the water, pH is an important indicator of water that is changing chemically. pH is reported in "logarithmic units," like the Richter scale, which measures earthquakes. Each number represents a 10-fold change in the acidity/basicness of the water. Water with a pH of 5 is ten times more acidic than water having a pH of six.
Pollution can change a water's pH, which in turn can harm animals and plants living in the water. For instance, water coming out of an abandoned coal mine can have a pH of 2, which is very acidic and would definitely affect any fish crazy enough to try to live in it! By using the logarithm scale, this mine-drainage water would be 100,000 times more acidic than neutral water -- so stay out of abandoned mines.

Specific conductance
Specific conductance is a measure of the ability of water to conduct an electrical current. It is highly dependent on the amount of dissolved solids (such as salt) in the water. Pure water, such as distilled water, will have a very low specific conductance, and sea water will have a high specific conductance. Rainwater often dissolves airborne gasses and airborne dust while it is in the air, and thus often has a higher specific conductance than distilled water. Specific conductance is an important water-quality measurement because it gives a good idea of the amount of dissolved material in the water.
Probably in school you've done the experiment where you hook up a battery to a light bulb and run two wires from the battery into a beaker of water. When the wires are put into a beaker of distilled water, the light will not light. But, the bulb does light up when the beaker contains salt water (saline). In the saline water, the salt has dissolved, releasing free electrons, and the water will conduct an electrical current.

Turbidity
Turbidity is the amount of particulate matter that is suspended in water. Turbidity measures the scattering effect that suspended solids have on light: the higher the intensity of scattered light, the higher the turbidity. Material that causes water to be turbid include:

• clay
• silt
• finely divided organic and inorganic matter
• soluble colored organic compounds
• plankton
• microscopic organisms

Turbidity makes the water cloudy or opaque. The picture to the left shows highly turbid water from a tributary (where construction was probably taking place) flowing into the less turbid water of the Chattahoochee River in Georgia. Turbidity is measured by shining a light through the water and is reported in nephelometric turbidity units (NTU). During periods of low flow (base flow), many rivers are a clear green color, and turbidities are low, usually less than 10 NTU. During a rainstorm, particles from the surrounding land are washed into the river making the water a muddy brown color, indicating water that has higher turbidity values. Also, during high flows, water velocities are faster and water volumes are higher, which can more easily stir up and suspend material from the stream bed, causing higher turbidities.
Turbidity can be measured in the laboratory and also on-site in the river. A handheld turbidity meter (left-side picture) measures turbidity of a water sample. The meter is calibrated using standard samples from the meter manufacturer. The picture with the three glass vials shows turbidity standards of 5, 50, and 500 NTUs. Once the meter is calibrated to correctly read these standards, the turbidity of a water sample can be taken.
http://ga.water.usgs.gov/edu/pictures/TurbiditySond.jpghttp://ga.water.usgs.gov/edu/picture...MeterClose.jpgState-of-the-art turbidity meters (left-side picture) are beginning to be installed in rivers to provide an instantaneous turbidity reading. The right-side picture shows a closeup of the meter. The large tube is the turbidity sensor; it reads turbidity in the river by shining a light into the water and reading how much light is reflected back to the sensor. The smaller tube contains a conductivity sensor to measure electrical conductance of the water, which is strongly influenced by dissolved solids (the two holes) and a temperature gauge (the metal rod).

Dissolved oxygen
Although water molecules contain an oxygen atom, this oxygen is not what is needed by aquatic organisms living in our natural waters. A small amount of oxygen, up to about ten molecules of oxygen per million of water, is actually dissolved in water. This dissolved oxygen is breathed by fish and zooplankton and is needed by them to survive.
Rapidly moving water, such as in a mountain stream or large river, tends to contain a lot of dissolved oxygen, while stagnant water contains little. Bacteria in water can consume oxygen as organic matter decays. Thus, excess organic material in our lakes and rivers can cause an oxygen-deficient situation to occur. Aquatic life can have a hard time in stagnant water that has a lot of rotting, organic material in it, especially in summer, when dissolved-oxygen levels are at a seasonal low.

Hardness
The amount of dissolved calcium and magnesium in water determines its "hardness." Water hardness varies throughout the United States. If you live in an area where the water is "soft," then you may never have even heard of water hardness. But, if you live in Florida, New Mexico, Arizona, Utah, Wyoming, Nebraska, South Dakota, Iowa, Wisconsin, or Indiana, where the water is relatively hard, you may notice that it is difficult to get a lather up when washing your hands or clothes. And, industries in your area might have to spend money to soften their water, as hard water can damage equipment. Hard water can even shorten the life of fabrics and clothes! Does this mean that students who live in areas with hard water keep up with the latest fashions since their clothes wear out faster?

imp:

:thumbsup:

[KL4D4]

wow this is very helpful