1) How much Sodium is added to my water with a water softener?
- The amount of sodium a water softener adds to tap water depends on the "hardness" of your water. The best way to decrease your sodium intake is by cutting back on table salt and processed foods. But the water from your tap also may add a significant amount of sodium to your diet. Reducing dietary sodium can lower systolic blood pressure by 2 to 8 millimeters of mercury (mm Hg). Hard water contains large amounts of calcium and magnesium — dissolved from the soil by rainwater. A typical water-softening system removes calcium and magnesium ions from hard water and replaces them with sodium ions. The higher the concentration of calcium and magnesium, the more sodium needed to soften the water. Your local health department can tell you the sodium and other mineral content of your community's water supply. (Water naturally contains some sodium before it's softened.) This information can help you determine the total amount of sodium your tap water may have before being softened. It can also help you estimate the amount of sodium (milligrams per liter) a softener adds to your water. Here's how: Ask your local health department for the hardness of your water in grains per gallon. Multiply this number by 8 — or 7.866 to be more precise. This tells you how much sodium is added to your water by softening. Add this figure to the amount of naturally occurring sodium in your water — also from your local health department — to determine the total sodium. One survey found that, as a general rule, an 8-ounce glass of softened tap water contains less than 12.5 milligrams of sodium. According to the Food and Drug Administration nutrient guidelines, this is in the very low-sodium range.
- 2) What is Reverse Osmosis?
- Reverse osmosis is a separation process that uses pressure to force a solvent through a membrane that retains the solute on one side and allows the pure solvent to pass to the other side. More formally, it is the process of forcing a solvent from a region of high solute concentration through a membrane to a region of low solute concentration by applying a pressure in excess of the osmotic pressure. This is the reverse of the normal osmosis process, which is the natural movement of solvent from an area of low solute concentration, through a membrane, to an area of high solute concentration when no external pressure is applied. The membrane here is semipermeable, meaning it allows the passage of solvent but not of solute. The membranes used for reverse osmosis have a dense barrier layer in the polymer matrix where most separation occurs. In most cases the membrane is designed to allow only water to pass through this dense layer while preventing the passage of solutes (such as salt ions). This process requires that a high pressure be exerted on the high concentration side of the membrane, usually 2–17 bar (30–250 psi) for fresh and brackish water, and 40–70 bar (600–1000 psi) for seawater, which has around 24 bar (350 psi) natural osmotic pressure which must be overcome. This process is best known for its use in desalination (removing the salt from sea water to get fresh water), but has also purified naturally occurring freshwater for medical, industrial process and rinsing applications since the early 1970s.
- 3) What is a water softener?
- A water softener reduces the calcium or magnesium ion concentration in hard water. These "hardness ions" cause three major kinds of problems. The metal ions react with soaps and calcium sensitive detergents, hindering their ability to lather properly and forming an unsightly precipitate— the familiar scum or "bathtub ring". Presence of "hardness ions" also inhibits the cleaning effect of detergent formulations. More seriously, calcium and magnesium carbonates tend to adhere to the surfaces of pipes and heat exchanger surfaces. The resulting scale build-up can restrict water flow in pipes. In boilers, the deposits act as thermal insulation that impedes the flow of heat into the water; this not only reduces heating efficiency, but allows the metal to overheat which, in a pressurized system, can lead to failure."
- 1. What is Activated Carbon?Carbon is an extremely porous material that attracts and holds a wide range of harmful contaminants. Activated carbon is carbon which has a slight electro-positive charge added to it, making it even more attractive to chemicals and impurities. As the water passes over the positively charged carbon surface, the negative ions of the contaminants are drawn to the surface of the carbon granules.
- 2. What forms does it come in?
- Activated carbon filters used for home water treatment typically contain either granular activated carbon (GAC) or powdered block carbon (carbon block).
- 3. Which is generally better, GAC or carbon block?
- Although both are effective, carbon block filters generally have a higher contaminant removal ratio and are more resistant to channeling.
- 4. Are all carbon filters equally effective?
- No. Activated carbon filters are usually rated by the size of particles they are able to remove, measured in microns, and generally range from 20 microns (least effective) down to 0.5 microns (most effective). The two most important factors affecting the efficiency of activated carbon filtration are the amount of activated carbon in the unit and the amount of time the contaminant spends in contact with it. The more carbon the better. Particle size also affects contaminant removal rates. The most common carbon types used in water filtration are bituminous, wood, centaur carbon and coconut shell carbons.
- 5. Can I use taste and flow rate to determine when to change the filter?
- No. These are very poor methods of monitoring your water filter for maintenance. Once the bad tastes have returned, it is already far too late - contaminants have passed through the filter and into your drinking water. A carbon cartridge may be able to control taste and odors long after the carbon has lost its ability to effectively reduce other toxic contaminants. You should always follow the manufacturer's filter replacement schedule to ensure optimal filtration.
- 6. What is Backwashing and do you recommend it?
- Backwashing is the process of forcing water through a filter in the wrong direction to unclog the dirt and sediment which has blocked the filter. Backwashing is a common practice for certain whole house and commercial units which are treating large volumes of water for utility purposes but it is not a recognized practice for small point of use drinking water systems.
- 7. What Contaminants Does Carbon (GAC) Remove?
- Activated carbon filters remove/reduce many volatile organic chemicals (VOC), pesticides and herbicides, as well as chlorine, benzene, trihalomethane (THM) compounds, radon, solvents and hundreds of other man-made chemicals found in tap water. Some activated carbon filters are moderately effective at removing some, but not all, heavy metals. In addition, densely compacted carbon block filters mechanically remove particles down to 0.5 micron, including Giardia and Cryptosporidium, turbidity and particulates. Although some iron, manganese, and hydrogen sulfide will be removed by these higher quality activated carbon filters, a manganese greensand iron reduction filter is generally preferred to remove these contaminants as the effectiveness of carbon filter against iron and manganese is generally short-lived if the contaminant concentration is high. Carbon filters are NOT generally successful at removing dissolved inorganic contaminants or metals such as minerals/salts (hardness or scale-causing contaminants), antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, copper, fluoride, mercury, nickel, nitrates/nitrites, selenium, sulfate, thallium, and certain radio nuclides. Removing these contaminants requires either a reverse osmosis water filter system or a distiller (some can also be removed by KDF-55 or manganese greensand). GAC does not remove sediment / particulate material very well, so they are often preceded by a sediment filter. Sediment pre-filters also prolong the activate carbon cartridge life by eliminating gross contaminants that would otherwise clog the activated carbon thereby reducing the surface area available for absorption. Carbon block filters are generally better then GAC filters at removing sediment.