What Is TDS?
HM DIGITAL
HM DIGITAL is rapidly becoming the industry leader and premier source for the finest quality water testing instrumentation.
HM DIGITAL's handheld and portable TDS, EC and pH testers, in-line monitors and controllers for reverse osmosis (RO) water filters and water purification systems are superior in construction and performance, yet made available at a very economic cost. HM DIGITAL, Inc. is the only manufacturer of economical in-line dual TDS meters that measure total dissolved solids (TDS) levels of feed and product water lines simultaneously, an effective way to compare rejection rates and gauge reverse osmosis membrane, water filter and water purification performance.
With HM DIGITAL water testing instruments, you'll know if your water is pure.
The following information about TDS and Water Quality is provided by HM DIGITAL:
What Are Total Dissolved Solids?
Total
Dissolved Solids (TDS) are the total amount of mobile charged ions,
including minerals, salts or metals dissolved in a given volume of
water, expressed in units of mg per unit volume of water (mg/L), also
referred to as parts per million (ppm). TDS is directly related to the
purity of water and the quality of water purification systems and
affects everything that consumes, lives in, or uses water, whether
organic or inorganic, whether for better or for worse.
"Dissolved solids" refer to any
minerals, salts, metals, cations or anions dissolved in water. This
includes anything present in water other than the pure water (H20)
molecule and suspended solids. (Suspended solids are any
particles/substances that are neither dissolved nor settled in the
water, such as wood pulp.)
In general, the total dissolved solids
concentration is the sum of the cations (positively charged) and anions
(negatively charged) ions in the water.
Parts per Million (ppm) is the weight-to-weight ratio of any ion to water.
A
TDS meter is based on the electrical conductivity (EC) of water. Pure
H20 has virtually zero conductivity. Conductivity is usually about 100
times the total cations or anions expressed as equivalents. TDS is
calculated by converting the EC by a factor of 0.5 to 1.0 times the EC,
depending upon the levels. Typically, the higher the level of EC, the
higher the conversion factor to determine the TDS. NOTE - While a TDS
meter is based on conductivity, TDS and conductivity are not the same
thing.
Where Do Dissolved Solids Come From?
Some
dissolved solids come from organic sources such as leaves, silt,
plankton, and industrial waste and sewage. Other sources come from
runoff from urban areas, road salts used on street during the winter,
and fertilizers and pesticides used on lawns and farms.
Dissolved
solids also come from inorganic materials such as rocks and air that
may contain calcium bicarbonate, nitrogen, iron phosphorous, sulfur,
and other minerals. Many of these materials form salts, which are
compounds that contain both a metal and a nonmetal. Salts usually
dissolve in water forming ions. Ions are particles that have a positive
or negative charge.
Water may also pick up metals such as lead or copper as they travel through pipes used to distribute water to consumers.
Note
that the efficacy of water purifications systems in removing total
dissolved solids will be reduced over time, so it is highly recommended
to monitor the quality of a filter or membrane and replace them when
required.
Why Should You Measure the TDS Level in Your Water?
The
EPA Secondary Regulations advise a maximum contamination level (MCL) of
500mg/liter (500 parts per million (ppm)) for TDS. Numerous water
supplies exceed this level. When TDS levels exceed 1000mg/L it is
generally considered unfit for human consumption. A high level of TDS
is an indicator of potential concerns, and warrants further
investigation. Most often, high levels of TDS are caused by the
presence of potassium, chlorides and sodium. These ions have little or
no short-term effects, but toxic ions (lead arsenic, cadmium, nitrate
and others) may also be dissolved in the water.
Even the best water purification systems on the market require monitoring for TDS to ensure the filters and/or membranes are effectively removing unwanted particles and bacteria from your water.
The following are reasons why it is helpful to constantly test for TDS:
- Taste/Health - High TDS results in undesirable taste which could be salty, bitter, or metallic. It could also indicate the presence of toxic minerals. The EPA's rescommended maximum level of TDS in water is 500mg/L (500ppm).
- Filter performance - Test your water to make sure the reverse osmosis or other type of water filter or water purification system has a high rejection rate and know when to change your filter (or membrane) cartridges.
- Hardness - High TDS indicates Hard water, which causes scale buildup in pipes and valves, inhibiting performance.
Aquariums/Aquaculture - A constant level of minerals is necessary for aquatic life. The water in an aquarium or tank should have the same levels of TDS and pH as the fish and reef's original habitat. - Hydroponics - TDS is the best measurement of the nutrient concentration in a hydroponic solution.
Pools and spas - TDS levels must be monitored to prevent maintenance problems. - Commercial/Industrial - High TDS levels could impede the functions of certain applications, such as boilers and cooling towers, food and water production and more.
- Colloidal silver water - TDS levels must be controlled prior to making colloidal silver.
- Coffee and Food Service - For a truly great cup of coffee, proper TDS levels must be maintained.
- Car and window washing - Have a washer with a spotless rinse? An inline dual TDS monitor will tell you when to change the filter cartridge or RO membrane.
What should the TDS level of my water be?
There
is no specific level nor right or wrong answer to this question.
Generally speaking, for drinking water, a lower level of TDS (purer
water) is preferred. The U.S. EPA, all U.S. states, the World Health
Organization (WHO) and most nations put maximum limitations on TDS
allowed in drinking water. These limitations are typically 500 or 1000
ppm, but they do vary. There is no known minimum.
Besides
drinking water, a TDS level is specific for each application and
particular usage. Though humans prefer purer water for their health,
fish and plants, for example, require water with widely varying TDS
levels, most of which are higher than healthy human drinking water. If
you are using a meter to test the water pertaining to a particular
device, object or operation, contact the manufacturer of that object.
For example, if you are using the meter to test the efficacy of a water
filtration system, contact the manufacturer of that system for
preferred TDS levels. If you are testing the water for a pool, plants,
fish, etc. contact a specialist for your specific application, or the
manufacturer of additives or nutrients.
Don’t you need the minerals in your drinking water?
Inorganic Minerals.
- It is believed that mineral waters help furnish elements for body metabolism. However, there is scientific proof to suggest that most of these minerals are in an inorganic (dead) form. While they may enter the circulation, they cannot be used in the physiological process of building the human cell.
- With this in mind, we can see that mineral water may give "dead" or "inorganic" minerals to the body which cannot be properly assimilated.
- These inorganic minerals only interfere with the delicate and complex biology of the body.
- The body's need for minerals is largely met through foods, NOT DRINKING WATER." -The American Medical Journal
- Fact: The organic minerals in tap water represent only 1% of the total mineral content of the water.
- One glass of orange juice contains more beneficial minerals than thirty gallons of untreated tap water.
Organic, or Bioavailable Minerals.
- Only after they have passed through the roots of plants do these inorganic minerals become organic (through photosynthesis) and capable of being assimilated into our tissues as ORGANIC Minerals.
- Pure water removes the inorganic mineral deposits in your body. Organic minerals are fully absorbed and remain in your tissues.
- According to many nutritionists minerals are much easier to assimilate when they come from foods. Can you imagine going out to your garden for a cup of dirt to eat rather than a nice carrot; or drinking a whole bathtub of water for LESS calcium than that in an 8 ounce glass of milk?
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