In this mid-June Occasional, you'll hear about a massive jellyfish, waterless dyeing, and how water shortage affects the poor and the beer industry. How fracking may cause drought, how a city's water supply was ruined by gluten contamination, how deep sea fishing may affect climate change, and how to test the TDS of your home RO unit. Hear about massive deep Earth oceans, a generous gift to polluters (including the US miltary) from the Supreme Court, the Ringwoodite reservoir, Uzbekistan's water problems, and a toxic muck cleanup in a New Jersey river. Then there's a scary story about plastiglomerate and an equally scary ban on xeriscaping in a ritzy Dallas neighborhood. Finally, a succinct explanation of TDS, brine, and brackish water, and as always, there is much, much more.
The Pure Water Occasional is a project of Pure Water Products and the Pure Water Gazette.
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City's Water Contaminated by an Irresponsible Child
Authorities in Portland, Ore. have discovered detectable levels of gluten in the city’s water supply, causing a citywide panic.
The city’s water bureau discovered the contamination yesterday and is desperately trying to find out how gluten got into the water. A preliminary report found that the contamination may have occurred “at least eight or nine months ago” when a child dropped a loaf of bread into a local river.
Officials have declared a state of emergency and plan to drain all of the city’s reservoirs. The mayor has also deployed city’s spiritual and wellness counselors to provide relief to beleaguered residents who drank the gluten-contaminated water.
“I haven’t seen anything like this since the Tofu Crisis of ‘08, when we discovered that the Pacific Northwest’s entire supply of tofu had been prepared alongside bacon,” said city engineer Bryce Shivers. “I imagine we’re going to be seeing the disastrous effects of this on the city for decades, like higher rates of obesity, cancer, brain damage and illiteracy.
“Or whatever it is that gluten does. Frankly, I have no idea. My Hot Yoga guru just gave me a brochure.”
Make it grain (free)
Gluten, a type of protein in wheats and certain grains, is found in numerous products including flour, pasta, pastries, beer, cereal, salad dressings and lip balm.
Although gluten-free food is recommended for people with celiac disease, it has become a fad diet for many, including millions in trendier-than-thou Portland. Gluten-free foods are becoming mainstream throughout the U.S. — even though very few consumers can explain what gluten is or why they think it’s bad.
“This is the worst news I’ve ever heard,” Portland resident Steve Arlo said as he sat drinking a microbrew made with barley and rye. “It’s like being told they dumped fluoride into the water supply. Wait! Have they dumped fluoride into the water supply?”
Dex Parios said she started her gluten-free diet “before anyone ever heard of it.” Now depressed by the news about the gluten, she is concerned that Portland is losing its reputation for livability and alternative lifestyles.
“When I moved here after getting my master’s degree in order to work part time at a record store, I thought Portland was a haven for intelligent, well-educated and cultured people,” she said. “But it’s so dangerous. Our leaders can’t even protect us from chemtrails, cell phone towers, bark dust fires, Republicans, people trying to talk to you, and now gluten outbreaks. It’s becoming like Baghdad or Afghanistan day by day.
“If I want to live in a city filled with provincial, arrogant, short-sighted morons, I’ll move to Gresham.”
Despite the paranoia gripping Portland’s streets, not all scientists are convinced by the city’s analysis and believe the water bureau has made a grave error.
“Gluten is not soluble in water, so it’s extremely unlikely to be found in tap water,” says Dr. Chaz Friday of Portland State University. “Nevertheless, just to be on the safe side perhaps hipsters with gluten-sensitivity should move to Seattle instead."
Source: The Daily Currant
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In more than two decades working at a Central California food bank, Sandy Beals has never seen anything like this spring.
Last month alone, FoodLink of Tulare County served 22,000 people who came in for food — 5,000 more than it usually serves each month and a 12 percent increase from the same month last year. For Beals, who runs the food bank, the spike in hunger traces back to one thing: drought.
“We didn’t think we would hit a big peak until August, but it’s already started to climb,” Beals says. "And it’s going to get a lot worse" as the end of the crop season normally drives more migrant workers to FoodLink's services.
Tulare County is just one of the hundreds of counties across the country experiencing drought, including every county in California, according to ratings by theU.S. Drought Monitor. Conditions are such that Gov. Jerry Brown declared a state of emergency in January.
The drought situation is driving up prices nationwide for produce grown in the Golden State's Central Valley and other agricultural areas stricken by drought, such asKansas, Oklahoma and Texas. And among rising food costs, access to clean water and growing unemployment, the drought’s hardest-hit victims are the country’s poor.
"We like to say we live in the greatest country in the world," says Melinda Laituri, a geography professor at Colorado State University who specializes in disaster management. "But in many ways, we manifest all the very worst things. (Drought) impacts the everyday life of everyone. But it has more impact on those who have fewer options and fewer choices to make."
Unlike tornadoes or hurricanes, relative to other natural disasters, drought often goes unnoticed, says historian Elke Weesjes, a disaster researcher at the University of Colorado. And dried-up land has especially devastating effects for those already facing the challenges of poverty.
“Drought doesn’t photograph well because the impact is very much hidden,” Weesjes says. “It’s translated into economic losses and whole communities are affected by drought."
"Sometimes it's easier to deal with too much of something — like a flood or a big storm that comes in. It's something we can respond to rapidly because it's an event," she says. "It's only after several years that we realize we are in a drought."
In Tulare County, 29.7 percent of residents live below the federal poverty line — making it the most impoverished county in the state and among the highest poverty rates in the nation. The drought has hit Tulare County's poor particularly hard, especially families like 80-year-old Carmen and Al Almanza. The retired couple were surprised in early April when water simply stopped coming out of their faucet.
They rely on their son, who brings a trash can filled with water to their home three times a week, and grandchildren, who bring them bottled water for drinking.
Local water authorities told the Almanzas their well was dry and they needed to dig about 150 feet deeper — which could cost anywhere from $7,000 to $15,000. The couple, living only on Social Security, say they can’t afford that kind of renovation.
“I just need my well fixed,” Carmen Almanza says. “You can imagine it’s difficult to open the faucet and expect to have plenty of water, and now we don’t.”
The couple’s problem is becoming more common throughout the Central Valley, where 90 percent of residents rely on groundwater. Residents must search elsewhere for water to meet basic needs like laundry, cooking, teeth brushing and showering. Many residents must buy their drinking water from grocery stores up to 15 miles away from their homes or individual bottles of water from convenience stores.
That's partly because even in places where wells haven't run dry, much of the groundwater has been contaminated by farming chemicals and low water levels. The problem of water contamination in the Central Valley has existed for decades, but the situation is exacerbated by the drought because less water means higher concentrations of nitrate and arsenic (among other contaminants).
The longer the drought persists, the higher the contamination, says Susana De Anda, executive director of Community Water Center, a California-based nonprofit organization that helps communities access clean water through funding and policy advocacy.
Small communities have little infrastructure to treat water for safe use, and water funding has been prioritized to bigger, more urban water needs. Even if clean water were available, it would be running through antiquated pipe systems that cause contamination, De Anda says.
The contamination also creates a financial burden on residents who have to buy potable water to replace the groundwater they pay for but can't use.
People in one community in Tulare County spend an average 3.9 percent of their household income on water expenses, according to a pilot study done by CWC. That exceeds the 1.5 percent affordability threshold recommended by the U.S. Environmental Protection Agency. And some households spend up to 10 percent of their income on water alone, De Anda says.
That means some families are spending $100 to $150 a month just on water, says CWC policy analyst Omar Carrillo. He says he knows families who are living on $14,000 a year, paying $100 a month in water bills for contaminated water and then buying bottled water on top of that for drinking. For some, that's more than they spend on groceries.
"There are trade-offs," Carrillo says, referring to sacrifices families make to pay for their most basic needs. "They'll end up without something."
Community Water Center has been working to help families access safe drinking water since 2006, and De Anda says she sees the state's drought emergency as an opportunity to leverage emergency federal funding that previously wasn't available for people who have been without clean water, even years before the onset of the drought.
CWC has made some short-term gains with $4 million in federal grants for emergency water supply in disadvantaged communities. As a result, residents of Tooleville, a small community in Tulare County, will soon receive free bottled water for three years. Other communities are applying for grants to provide free clean water either from vending machines or by delivery. These are short-term solutions, to be sure, but the water provided by emergency funding is a huge relief for families with steep water bills, De Anda says.
Plus, within the next month, Tulare County’s Community Action Agency will begin offering assistance with water bills. It's a service it typically can't afford, usually only offering help with electricity and gas bills. But Brown recently signed off on a drought relief package of roughly $686 million, $28.5 million of which is allocated specifically for emergency drinking water and water supply.
Water is food
But the impact of the drought on the Central Valley's poor isn't limited to water problems.
Tulare County sits in the center of California's Central Valley, which supplies up to half of the nation's fruit, nuts and vegetables, according to the California Department of Food and Agriculture. Prices of produce like avocados, lettuce and grapes have increased dramatically, according to the Bureau of Labor Statistics' Consumer Price Index, and are only expected to increase.
The price of avocados, for instance, is expected to increase between 17 and 35 cents due to drought,estimates Arizona State University researcher Timothy Richards. Consumers all across the country have felt the impacts of rising food prices, but those costs weigh heavily on the poor, says FoodLink’s Beals.
Families living in poverty spend roughly 21 percent of their household budget on food alone, more than twice the percentage average Americans spend, according to the Bureau of Labor Statistics. And higher prices for healthy foods like fresh produce exacerbate the long-established link between poverty and obesity as low-income families maximize their calories per dollar. Plus, 11.5 million poor Americans live in a low-income area over a mile away from a grocery store, according to a report from the U.S. Department of Agriculture.
Most of the donations FoodLink relies on are food and money that come from the agricultural community, and Beals says even though the drought relief funding allocates $25 million for disaster boxes of food staples like rice, beans and canned vegetables, she mourns the loss of the healthy food donated by farmers in the area. “We pride ourselves on giving fresh produce, but that is no longer true,” she said. “We’re going to be getting less help.”
That's why De Anda and the Community Water Center are intent to improve policies regarding water. If an apple is food, water is food too, De Anda says. And clean water is where it starts.
Source: Deseret News.
Scientists say rock layer hundreds of miles down holds vast amount of water, opening up new theories on how planet formed
After decades of searching scientists have discovered that a vast reservoir of water, enough to fill the Earth’s oceans three times over, may be trapped hundreds of miles beneath the surface, potentially transforming our understanding of how the planet was formed.
The water is locked up in a mineral called ringwoodite about 660km (400 miles) beneath the crust of the Earth, researchers say. Geophysicist Steve Jacobsen from Northwestern University in the US co-authored the study published in the journal Science and said the discovery suggested Earth’s water may have come from within, driven to the surface by geological activity, rather than being deposited by icy comets hitting the forming planet as held by the prevailing theories.
“Geological processes on the Earth’s surface, such as earthquakes or erupting volcanoes, are an expression of what is going on inside the Earth, out of our sight,” Jacobsen said.
“I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades.”
Jacobsen and his colleagues are the first to provide direct evidence that there may be water in an area of the Earth’s mantle known as the transition zone. They based their findings on a study of a vast underground region extending across most of the interior of the US.
Ringwoodite acts like a sponge due to a crystal structure that makes it attract hydrogen and trap water.
If just 1% of the weight of mantle rock located in the transition zone was water it would be equivalent to nearly three times the amount of water in our oceans, Jacobsen said.
The study used data from the USArray, a network of seismometers across the US that measure the vibrations of earthquakes, combined with Jacobsen’s lab experiments on rocks simulating the high pressures found more than 600km underground.
It produced evidence that melting and movement of rock in the transition zone – hundreds of kilometres down, between the upper and lower mantles – led to a process where water could become fused and trapped in the rock.
The discovery is remarkable because most melting in the mantle was previously thought to occur at a much shallower distance, about 80km below the Earth’s surface.
Jacobsen told the New Scientist that the hidden water might also act as a buffer for the oceans on the surface, explaining why they have stayed the same size for millions of years. "If [the stored water] wasn't there, it would be on the surface of the Earth, and mountaintops would be the only land poking out," he said.
Source: The Guardian.
Melted plastic trash on beaches can sometimes mix with sediment, basaltic lava fragments and organic debris (such as shells) to produce a new type of rock material, new research shows.
Plastiglomerate. Click picture for larger view.
The new material, dubbed plastiglomerate, will forever remain in Earth's rock record, and in the future may serve as a geological marker for humankind's impact on the planet, researchers say.
Plastic pollution is a worldwide problem affecting every waterway, sea and ocean in the world, according to the Natural Resources Defense Council. First produced in the 1950s, plastic doesn't break down easily and is estimated to persist in the environment for hundreds to thousands of years. Plastic debris is also lightweight, allowing it to avoid being buried and becoming a part of the permanent geological record.
But while at Hawaii's Kamilo Beach, Capt. Charles Moore, an oceanographer with the Algalita Marine Research Institute in California, found that plastic, if melted, can actually become one with rocks, sediment and other geologic materials. [See Images of the Plastiglomerate Rock at Kamilo]
"He found some plastic had been melted to rocks, and other pieces of natural material had also been stuck on it," said study lead author Patricia Corcoran, a geologist at the University of Western Ontario (UWO) in Canada. "He didn't know what to call it. It's possible other people have found [the plastic conglomerates] at other locations before Captain Moore did, but nobody had thought to report it or identify it."
Corcoran attended a presentation Moore gave about his find, and she became immediately interested in investigating the material. So she, along with Moore and Kelly Jazvac, a visual artist at UWO, headed to Kamilo Beach to analyze the plastic formations.
A human origin
Kamilo Beach, located on the southeastern tip of the Big Island of Hawaii, is often considered to be one of the dirtiest beaches in the world. Because of the current flow and high wave energy of the area, the beach is covered with plastic debris pulled in from the ocean, including fishing gear, food and drink containers and multicolored plastic fragments called "plastic confetti."
The researchers discovered there are two types of plastiglomerates at Kamilo Beach: In situ and clastic.
In situ plastiglomerate is more rare than the clastic variety, and forms when "plastic melts on rock and becomes incorporated into the rock outcrop," Corcoran told Live Science, adding that the melted plastic can also get into the rock vesicles, or cavities. Clastic plastiglomerates, on the other hand, are loose rocky structures, composed of a combination of basalt, coral, shells, woody debris and sand that have been glued together by melted plastic.
When Moore first discovered Kamilo Beach's plastiglomerates, he hypothesized that molten lava had melted the plastic to create the new rock. However, the researchers found that lava had not flowed in that area since before plastics were first invented.
After digging further into the mystery and talking with locals, the researchers concluded that people inadvertently created the plastiglomerates after burning plastic debris, either intentionally to try to destroy the plastic or accidentally by way of campfires.
Given this origin for the beach's plastiglomerates, the team thinks the material could be present at a lot of other beaches around the world, particularly in areas where people camp or live.
"I would say that anywhere you have abundant plastic debris and humans, there will probably be plastiglomerates," Corcoran said. Additionally, other locations where there is both active volcanism and beaches polluted with plastic, such as Iceland and the Canary Islands, could have lava-produced plastiglomerates, she said.
A global marker
At present, we live in the Holocene Epoch, which began nearly 12,000 years ago. In recent years, scientists have debated whether to formally identify a new geological era called the Anthropocene, which would mark the time period when human influence significantly altered Earth's physical, chemical and biological landscape. However, scientists can't agree when the Anthropocene should begin.
Whatever the case, there are several lines of evidence that highlight humankind's impact on the planet.
For instance, with the onset of the Industrial Revolution, a lot of carbon dioxide and other greenhouse gases have been pumped into the atmosphere. And even further back, the rise of agriculture some 8,000 years ago fundamentally changed land use and led to increased atmospheric carbon dioxide and methane, as evidenced from analyses of ice cores. Additionally, soil profiles from peat bogs indicate that mining activities and the combustion of leaded gasoline have resulted in increased lead concentrations over the past 300 years, the researchers noted in their study.
With plastiglomerates, scientists now have another global marker for the Anthropocene, Corcoran said. "It definitely shows how humans have interacted with Earth's biophysical system."
What's more, Corcoran and her colleagues have analyzed the clastic plastiglomerates from Kamilo Beach, and found the new material is far denser than plastic-only particles. This suggests plastiglomerates have a much greater potential to become buried and preserved in the rock record than normal plastic debris, and that future generations of scientists will be able to look into the planet's geological record and find the plastiglomerates.
"One day in the future, people can look at this material and use it as a marker horizon to see that in around 2010, humans were polluting the planet with plastic," Corcoran said. "But that's not a legacy we really want."
Source: Live Science
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Threat to critical waterways reveals a US-Canada divide. They are the invisible waterways. Laced with farm manure, choked with invasive grasses and often seasonally dry, their subtle meanderings go unnoticed and unappreciated. There are hundreds of them in the Fraser Valley, providing critical habitat for endangered fish and frogs against a tide of government neglect, poor farming practices and public ignorance.
Deep sea fishing threatens to wipe out a $150 billion carbon sink. Marine life in the high seas soak up an amount of carbon equivalent to 30 percent of the US’s annual emissions, a carbon-sequestering service worth about $148 billion a year. At the same time, increased fishing activity threatens the whole process.
Water woes force big brewers to tighten the tap. Some of the largest brewers in the U.S. are trying to reduce their water-to-beer ratio as drought and wildfire threaten the watersheds where they draw billions of gallons every year.
Removal of toxic muck from Passaic River in New Jersey a 'pilot project' for massive clean-up. The $20 million project, near Riverside County Park in Lyndhurst, is just a small part of what officials from the U.S. Environmental Protection Agency expect to be one of the largest federal Superfund projects in history.
The Supreme Court has ruled against homeowners in NC toxic water suit. The Supreme Court ruled in early June that a group of homeowners in North Carolina can't sue a company that contaminated their drinking water decades ago because a state deadline has lapsed, a decision that could prevent thousands of other property owners in similar cases from recovering damages after being exposed to toxic waste. In dissent, Justice Ruth Bader Ginsburg said Congress was concerned about state statutes that "deprive plaintiffs of their day in court." That concern is apparent in the case of diseases like cancer that take years to develop before a victim understands the cause, she said. Ginsburg said the majority's decision "gives contaminators an incentive to conceal the hazards they have created until the repose period has run its full course." She was joined in dissent by Justice Stephen Breyer.
The 120-foot-long jellyfish that’s loving global warming. This monster that once starred in a Sherlock Holmes mystery is really, really loving the whole global warming thing, conquering more and more of Earth’s oceans in massive blooms. So please, if you will, welcome our new giant gelatinous overlords.
New Jersey is planning to spend approximately $1.28 billion next year on a range of projects designed to improve the environmental infrastructure of the systems that deliver clean drinking water to residents and eliminate harmful substances in sewage discharged into New Jersey’s waterways.
Can water-less dyeing processes clean up the clothing industry? One of the world’s most polluting industries is the textile-dyeing sector, which in China and other Asian nations releases trillions of liters of chemically tainted wastewater. But new water-less dyeing technologies, if adopted on a large scale, could sharply cut pollution from the clothing industry.
Clean drinking water is a luxury for most Uzbeks. Water supply systems in Uzbekistan are not able to provide Uzbeks with enough clean drinking water even in regions that have natural sources of water.
Camp Lejeune Victims of the US Military's Negligence May Be Out Of Luck Because of the Recent Supreme Court Ruling in North Carolina
The U.S. Supreme Court has ruled (see article above) that North Carolina families cannot pursue lawsuits against the company that was responsible for contaminating their drinking water decades ago. Potential claims from other affected people could also be blocked, media reports said this week.
Water contamination caused by CTS Corp.'s electronics plant some 30 years ago was discovered decades after the facility was closed but a North Carolina law bans lawsuits filed more than 10 years after the event from being heard. With a 7-2 majority, the Supreme Court decided that that law was not superseded by federal law stating that victims could seek damages two years after the contamination had come to light.
While the ruling only concerns claims against the electronics company, it is expected to have implications for another landmark case taking place in North Carolina. Families of thousands of victims of the water contamination at Camp Lejeune who have spent years in legal battles with the Navy are likely to see their claims brought to an end too, according to reports.
Water contamination at the Navy base is estimated to have affected around 13,000 families, with children born there between the 1950s and 1985 as much as four times more likely to develop serious birth defects such as spina bifida, the U.S. Centers for Disease Control and Prevention revealed.
Source: Waste/Water Processing.
Fracking water use in Ohio may lead to droughts. With some groups touting the economic benefit hydraulic fracturing could have locally, scientists fear the effect of current trends for the future of Ohio's Muskingum River Watershed. The district is considering the sale of large amounts of freshwater to the shale drilling industry at a low price — $4.25 per 1,000 gallons. The $4.25 per 1,000 gallon fee is almost like giving the water away and with a $7 million well only accounts for 0.23 percent of capital expenditures. This is clearly a case of public welfare for the rich.
A Dallas man worked hard on his water-saving native-plant landscaping. But the Dallas Landmark Commission ruled that it was aesthetically inappropriate for the Junius Heights neighborhood in East Dallas. A Dallas News reader gave his opinion.
TDS stands for “Total Dissolved Solids.” Solids might also called dissolved minerals, ionic species, or salts. TDS is usually measured in ppm (parts per million) or mg/L (milligrams per liter), which are essentially the same. TDS is, in short, a measurement of all the dissolved mineral content of the water. A test for TDS does not measure chemicals or pathogens; a low TDS count does not mean that water is safe to drink.
TDS is measured often by laboratories with a conductivity meter, which quantifies the water's ability to conduct electricity. The higher the mineral content, the better it conducts electricity. For more practical purposes, a TDS meter, which works on the same principle, is used. Conductivity is read in micromhos per centimeter. The familiar TDS meter, an inexpensive and very handy tool, converts conductivity to ppm TDS for convenience.
The TDS Tester is an effective tool that gives an instant reading of any water. Just turn it on and insert the bottom part of the tester into the water. More information.
There is often confusion about TDS meters and what the readings mean. TDS meters measure the performance of reverse osmosis units, distillers, and deionizers, but except for limited use by professionals, they do not measure the performance of filters or water softeners. Softeners and filters do not affect TDS readings significantly. A softener, to illustrate, removes calcium and magnesium ions but the TDS reading will not be affected significantly because the softener adds a more-or-less equal amount of sodium in exchange. The TDS reading of softened water is usually slightly higher than the TDS of the untreated water. You need a hardness test to judge softener performance, not a TDS meter. Filters, especially when they are new, usually add TDS (the phenomenon is called “TDS throw”). Likewise, the performance of softener alternatives, either tank-style or electronic, cannot be measured by a TDS meter.
Classifying Water by TDS
Although other TDS classifications may differ slightly, here is a good basic TDS breakdown from a publication of the Water Quality Association of America:
TDS, in mg/L
Highly Brackish Water
Note that in standard usage these classifications are applied loosely. “Brine,” is used in water treatment for the salty water used to regenerate a softener or for the reject water from a reverse osmosis unit. In the case of the RO unit, the “brine” (a.k.a. “concentrate”) could be less than 50 mg/L in TDS. And although the song says that the moon was bright and shiny out on the briney, even sea water doesn't technically qualify as brine. Similarly, saline often means any salty solution, and brackish is often used just to mean really bad water without specific reference to its TDS.
The EPA suggests an upper TDS limit for drinking water of 500, although many cities exceed this limit without dire consequences. For residential water use, when water gets above 1,000 TDS it is starting to border on being unusable, although some well owners grit their teeth and put up with problems like badly stained fixtures, stopped up plumbing, or water so high in sodium that it isn't good for plants. Actually fairly high TDS water can be usable but it isn't pleasant to deal with.
Hardness does not always result from high TDS. In our area in Texas, for example, much of the well water is high in sodium but naturally soft. If water has a TDS of 600 and a hardness reading of 2 grains (about 35 ppm), you can be virtually certain that it has a lot of sodium in it. If the high TDS consists mainly of calcium and magnesium (the hardness minerals), it can be softened, but the resulting water will be high in sodium.
Treating High and Low TDS
Treating low TDS is not common, but it can be done by using filters with a sacrificial medium like calcite. As water passes through the filter, it dissolves some mineral content and the TDS goes up. This can be done for point of entry (whole house) or point of use (drinking water only) applications. Small filters are now often used to “remineralize” reverse osmosis water. Minerals are dissolved by the low TDS water passing through the filter, raising the TDS count.
Lowering TDS is done by reverse osmosis, the most common method used in residential settings, distillation, or deionization. Reverse osmosis reduces TDS 90%+ (99% for larger, high pressure units), while distillation and DI (deionization) units can reduce TDS to a zero meter showing. Filters do not reduce TDS, not even the extremely tight ones.
Practical TDS Tips for Residential RO Users
The main use for a handheld TDS tester is to verify the performance of your RO unit's membrane. While TDS is not in itself a targeted “contaminant” like lead, arsenic, or nitrates, the TDS meter verifies the health of the RO membrane. If the RO unit is reducing dissolved solids by 90%, you can be sure it's also doing a good job on aluminum and fluoride.
The purpose of the TDS test is to tell you when to change your membrane. If you have an excellent TDS reading, that does not mean you don't need to change your filter cartridges. The membrane should be changed on need—as indicated by the TDS test—but cartridges are changed on time. In fact, keeping the cartridges fresh is the best way to protect your membrane.
The worst time to do a TDS test is immediately after changing your filter cartridges. The new carbon postfilter will produce a "TDS throw” that will make your TDS reading high. Take a TDS test before you change your cartridges. The same principle applies to new RO units. You won't get a reliable TDS test until the unit is a couple of weeks old. If you want to test shortly after installation, take loose the tube going into the storage tank and take your sample there—before the water goes through the post filter.
An acceptable TDS reading is a matter of personal preference. On our residential RO units, we usually change membranes when the unit consistently fails to reduce TDS by 85% or so.
To determine this, test first the tap water from the faucet, then compare it with the water coming out of the RO unit. This is called "% rejection," and the formula is TDS of tap water minus TDS of RO water divided by TDS of tap water times 100. To illustrate, our local tap water usually runs around 180 TDS. So, if we test an RO system that shows a TDS reading of 15, the arithmetic would be 180 minus 15 = 165 divided by 180 = around 9.16 X 100 = about 92% rejection.
The best advice is don't obsess over TDS readings from a home unit. TDS is somewhat fickle and can be changed by variables like water pressure and the amount of water being used. Don't be too quick to change a membrane if you get one bad test.
Please visit our RO Parts Page for tanks and accessories.
Places to Visit on Our Websites in the meantime.
Garden Hose Filters. Don’t be the last on your block to own one.
Model 77: “The World’s Greatest $77 Water Filter”
”Sprite Shower Filters: You’ll Sing Better!”
An Alphabetical Index to Water Treatment Products
Our famous whole house Chloramine Catcher
Pure Water Occasional Archive: Sept. 2009-April 2013.
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