overshot is hot free sample

In Overshot is Hot! Weaver’s magazine Editor Madelyn van der Hoogt presents the many articles and projects featuring overshot that appeared in Weaver’s and Prairie Wool Companion over a period of almost 20 years. During that time, overshot was transformed from a weave structure—used mostly for coverlets or placemat borders—into a contemporary, multicolor, multiuse pattern weave.

Innovative designers explore and apply variations and extensions of overshot drafting techniques and share their results on these pages. This book is your chance to have it all under one cover.

Our books are formatted in rich Portable Document Format (PDF)—which includes bookmarking, internal page links, and high-res images & charts so you can print pages if you wish. For best results, we recommend using Acrobat Reader (a free application from Adobe™) as a desktop application for viewing and printing. Acrobat Reader 6 or higher is required to take advantage of all the features listed above. This PDF can be transferred to your tablet with all of the same functionality when you use one of many apps (like iBooks in iOS).

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This post is the third in a series introducing you to common weaving structures. We’ve already looked at plain weave and twill, and this time we’re going to dive into the magic of overshot weaves—a structure that’s very fun to make and creates exciting graphic patterns.

Overshot is a term commonly used to refer to a twill-based type of weaving structure. Perhaps more correctly termed "floatwork" (more on that later), these textiles have a distinctive construction made up of both a plain weave and pattern layer. Requiring two shuttles and at least four shafts, overshot textiles are built using two passes: one weaves a tabby layer and the other weaves a pattern layer, which overshoots or floats, above.

Readers in the United States and Canada may be familiar with overshot textiles through woven coverlets made by early Scottish and English settlers. Using this relatively simple technique, a local professional weaver with a four-shaft loom could easily make a near-infinite variety of equally beautiful and complex patterns. If you’d like to learn more about overshot coverlets and some of the traditions that settlers brought with them, please see my reading list at the bottom of this article!

As it is twill-based, overshot will be very familiar to 4 shaft weavers. It’s made up of a sequence of 2-thread repeats: 1-2, 2-3, 3-4, and 1-4. These sequences can be repeated any number of times to elongate and create lines, curves, and shapes. These 2-thread repeats are often referred to as blocks or threading repeats, IE: 1-2 = block 1/A, 2-3 = block 2/B.

There are three ways weft appears on the face of an overshot cloth: as a solid, half-tone, or blank. In the draft image I’ve shared here, you can see an example of each—the solid is in circled in blue, the half-tone in red, and the blank yellow. Pressing down the first treadle (shafts 1 and 2), for example, creates solid tones everywhere there are threads on shafts 1 and 2, half-tones where there is a 1 or 2 paired with 3 or 4, and nothing on the opposite block, shafts 3 and 4. Of course, there’s not really nothing—the thread is simply traveling on the back of the cloth, creating a reverse of what’s on the face.

Because overshot sequences are always made up of alternating shafts, plain weave can be woven by tying two treadles to lift or lower shafts 1-3 and 2-4. When I weave two-shuttle weaves like overshot, I generally put my tabby treadles to the right and treadle my pattern picks with my left foot and my tabby with my right. In the draft image I’ve shared above, I’ve omitted the tabby picks to make the overarching pattern clearer and easier to read. Below is a draft image that includes the tabby picks to show the structure of the fabric.

Traditional overshot coverlets used cotton or linen for warp and plain weave wefts, and wool pattern wefts—but there’s no rule saying you have to stick to that! In the two overshot patterns I’ve written for Gist, I used both Mallo and Beam as my pattern wefts.

In the Tidal Towels, a very simple overshot threading creates an undulating wave motif across the project. It’s easy and repetitive to thread, and since the overshot section is relatively short, it’s an easy way to get a feel for the technique.

The Bloom Table Squares are designed to introduce you to a slightly more complex threading—but in a short, easy-to-read motif. When I was a new weaver, one of the most challenging things was reading and keeping track of overshot threading and treadling—but I’ve tried to make it easy to practice through this narrow and quick project.

Overshot works best with a pattern weft that 2-4 times larger than your plain weave ground, but I haven’t always followed that rule, and I encourage you to sample and test your own wefts to see how they look! In the samples I wove for this article, I used 8/2 Un-Mercerized Cotton weaving yarn in Beige for my plain weave, and Duet in Rust, Mallo in Brick, and Beam in Blush for my pattern wefts.

The Bloom Table Squares are an excellent example of what weavers usually mean when they talk about traditional overshot or colonial overshot, but I prefer to use the term "floatwork" when talking about overshot. I learned this from the fantastic weaver and textile historian Deborah Livingston-Lowe of Upper Canada Weaving. Having researched the technique thoroughly for her MA thesis, Deborah found that the term "overshot" originated sometime in the 1930s and that historical records variably called these weaves "single coverlets’ or ‘shotover designs.’ Deborah settled on the term "floatwork" to speak about these textiles since it provides a more accurate description of what’s happening in the cloth, and it’s one that I’ve since adopted.

Long out of print, this fabulous book covers the Burnham’s extensive collection of early settler textiles from across Canada, including basic threading drafts and valuable information about professional weavers, tools, and history.

This book contains the collected drafts and work of Frances L. Goodrich, whose interest in coverlets was sparked when a neighbor gifted her one in the 1890s. Full of charming hand-painted drafts, this book offers a glimpse into North Carolina’s weaving traditions.

Amanda Ratajis an artist and weaver living and working in Hamilton, Ontario. She studied at the Ontario College of Art and Design University and has developed her contemporary craft practice through research-based projects, artist residencies, professional exhibitions, and lectures. Subscribe to herstudio newsletteror follow her onInstagramto learn about new weaving patterns, exhibitions, projects, and more.

A beautiful set of sample cards displaying all of our luscious yarns with over 500 colours. Each 8″ sample of yarn is organized in analogous colour harmony allowing for easy colour designing. Most of our cards include suggested weaving setts for plain weave, twill and supplemental wefts. 8/2 & 8/4 Cottons, Venne Cottolin, Yarns to Dye For, Harrisville Shetland, Jagger Spun Super Fine Merino, Zephyr Wool-Silk, Brushed Mohair, 100% Cotton Bouclé and 2/16 Cotton, JST Linen, Bamboo 7g & 12 g, Organic Cotton, Hot Line of Hand Dyed Silks

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With more than 30 of the best overshot projects compiled from 20 years of Weaver"s magazine and Prairie Wool Companion, this weaver’s reference combines step-by-step instructions with weaving theory. Such projects as heirloom linens, traditional coverlets, and colorful modern applications for scarves, table toppers, and wall hangings are presented, covering everything a crafter needs to know to design fabulous fabrics in overshot and its cousin star-and-diamond weave. Both beginners and advanced weavers working on at least four-shaft looms will delight in the projects provided.

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In economics, hot money is the flow of funds (or capital) from one country to another in order to earn a short-term profit on interest rate differences and/or anticipated exchange rate shifts. These speculative capital flows are called "hot money" because they can move very quickly in and out of markets, potentially leading to market instability.

The following simple example illustrates the phenomenon of hot money: In the beginning of 2011, the national average rate of one year certificate of deposit in the United States is 0.95%. In contrast, China"s benchmark one year deposit rate is 3%. The Chinese currency (renminbi) is seriously undervalued against the world"s major trading currencies and therefore is likely to appreciate against the US dollar in the coming years. Given this situation, if an investor in the US deposits his or her money in a Chinese bank, the investor would get a higher return than if he or she deposits money in a US bank. This makes China a prime target for hot money inflows. This is just an example for illustration. In reality, hot money takes many different forms of investment.

The following description may help further illustrate this phenomenon: "One country or sector in the world economy experiences a financial crisis; capital flows out in a panic; investors seek a more attractive destination for their money. In the next destination, capital inflows create a boom that is accompanied by rising indebtedness, rising asset prices and booming consumption - for a time. But all too often, these capital inflows are followed by another crisis. Some commentators describe these patterns of capital flow as "hot money" that flows from one sector or country to the next and leaves behind a trail of destruction."

The types of capital in the above categories share common characteristics: the investment horizon is short, and they can come in quickly and leave quickly.

There is no well-defined method for estimating the amount of hot money flowing into a country during a period of time, because hot money flows quickly and is poorly monitored. In addition, once an estimate is made, the amount of hot money may suddenly rise or fall, depending on the economic conditions driving the flow of funds. One common way of approximating the flow of hot money is to subtract a nation’s trade surplus (or deficit) and its net flow of foreign direct investment (FDI) from the change in the nation"s foreign reserves.

Hot money usually originates from the capital-rich, developed countries that have lower GDP growth rate and lower interest rates compared to the GDP growth rate and interest rate of emerging market economies such as India, Brazil, China, Turkey, Malaysia etc. Although the specific causes of hot money flow are somewhat different from period to period, generally, the following could be considered as the causes of hot money flow:

Emerging market countries began to adopt sound monetary and fiscal policies as well as market-oriented reforms including trade and capital market liberalization. Such policy reforms, among others, have resulted in a credible increase in the rate of return on investments.

As described above, hot money can be in different forms. Hedge funds, other portfolio investment funds and international borrowing of domestic financial institutions are generally considered as the vehicles of hot money. In the 1997 East Asian Financial Crisis and in the 1998 Russian Financial Crisis, the hot money chiefly came from banks, not portfolio investors.

However, large and sudden inflows of capital with a short term investment horizon have negative macroeconomic effects, including rapid monetary expansion, inflationary pressures, real exchange rate appreciation and widening current account deficits. Especially, when capital flows in volume into small and shallow local financial markets, the exchange rate tends to appreciate, asset prices rally and local commodity prices boom. These favorable asset price movements improve national fiscal indicators and encourage domestic credit expansion. These, in turn, exacerbate structural weakness in the domestic bank sector. When global investors" sentiment on emerging markets shift, the flows reverse and asset prices give back their gains, often forcing a painful adjustment on the economy.

Inflow of massive capital with short investment horizon (hot money) could cause asset prices to rallyinflation to rise. The sudden inflow of large amounts of foreign money would increase the monetary base of the receiving country (if the central bank is pegging the currency), which would help create a credit boom. This, in turn, would result in such a situation in which "too much money chases too few goods". The consequences of this would be inflation.

Furthermore, hot money could lead to exchange rate appreciation or even cause exchange rate overshooting. And if this exchange rate appreciation persists, it would hurt the competitiveness of the respective country"s export sector by making the country"s exports more expensive compared to similar foreign goods and services.

Sudden outflow of hot money, which would always certainly happen, would deflate asset prices and could cause the collapse value of the currency of respective country. This is especially so in countries with relatively scarce internationally liquid assets. There is growing agreement that this was the case in the 1997 East Asian Financial Crisis. In the run-up to the crises, firms and private firms in South Korea, Thailand and Indonesia accumulated large amounts of short-term foreign debt (a type of hot money). The three countries shared a common characteristic of having large ratio of short term foreign debt to international reserves. When the capital started to flow out, it caused a collapse in asset prices and exchange rates. The financial panic fed on itself, causing foreign creditors to call in loans and depositors to withdraw funds from banks. All of these magnified the illiquidity of the domestic financial system and forced yet another round of costly asset liquidations and price deflation. In all of the three countries, the domestic financial institutions came to the brink of default on their external short term obligations.

However, some economists and financial experts argue that hot money could also play positive role in countries that have relatively low level of foreign exchange reserves, because the capital inflow may present a useful opportunity for those countries to augment their central banks" reserve holdings.

Generally speaking, given their relatively high interest rates compared with that of the developed market economies, emerging market economies are the destination of hot money. Although the emerging market countries welcome capital inflows such as foreign direct investment, because of hot money"s negative effects on the economy, they are instituting policies to stop hot money from coming into their country in order to eliminate the negative consequences.

Exchange rate appreciation: the exchange rate can be used as a tool to control the inflow of hot money. If the currency is believed to be undervalued, that would be a cause of hot money inflow. In such circumstance, economists usually suggest a significant one-off appreciation rather than a gradual move in the exchange rate, as a gradual appreciation of the exchange rate would attract even more hot money into the country. One downside of this approach is that exchange rate appreciation would reduce the competitiveness of the export sector.

Interest rate reduction: countries that adopt this policy would lower their central bank"s benchmark interest rates to reduce the incentive for inflow. For example, on December 16, 2010, the Turkish Central Bank surprised markets by cutting interest rates at a time of rising inflation and relatively high economic growth. Erdem Basci, deputy bank governor of Turkish Central Bank argued that gradual rate cuts were the best way to prevent excessive capital inflows fuelling asset bubbles and currency appreciation.

Increasing bank reserve requirements and sterilization: some countries pursue a fixed exchange rate policy. In the face of large net capital inflow, those countries would intervene in the foreign exchange market to prevent exchange rate appreciation. Then sterilize the monetary impact of intervention through open market operations and through increasing bank reserves requirements.US dollars and buy Chinese yuan in the foreign exchange market. This would put upward pressure on the value of the yuan. In order to prevent the appreciation of the Chinese currency, the central bank of China print yuan to buy US dollars. This would increase money supply in China, which would in turn cause inflation. Then, the central bank of China has to increase bank reserve requirements or issue Chinese government bonds to bring back the money that it has previously released into the market in the exchange rate intervention operation. However, like other approaches, this approach has limitations. The first, the central bank can"t keep increasing bank reserves, because doing so would negatively affect bank"s profitability. The second, in the emerging market economies, the domestic financial market is not deep enough for open market operations to be effective.

Fiscal tightening: the idea is to use fiscal restraint, especially in the form of spending cuts on nontradables, so as to lower aggregate demand and curb the inflationary impact of capital inflow.

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Note: By their nature, radar images use color as a means of communicating information. This can be a problem for people with color vision deficiency. Visolve is a software application (free for personal use) that transforms colors of the computer display into the discriminable colors for various people including people with color vision deficiency, commonly called color blindness.

Reflectivity images are just as they sound as they paint a picture of the weather from the energy reflected back to the radar. Reflectivity images are the vast majority of radar images you will see on television as well. There are two types available on the web; Base Reflectivity (½° elevation) and Composite Reflectivity.

This image (right)(above) is a sample base reflectivity image from the Doppler radar in Frederick, OK. The radar is located in the center of the image.

The colors represent the strength of returned energy to the radar expressed in values of decibels (dBZ). The color scale is located at the lower right of each image. As dBZ values increase so does the intensity of the rainfall.

Value of 20 dBZ is typically the point at which light rain begins. The values of 60 to 65 dBZ is about the level where 1" (2.5 cm) diameter hail can occur. However, a value of 60 to 65 dBZ does not mean that severe weather is occurring at that location.

Hail that is totally frozen (without a thin layer of water in the surface). "Dry hail" is a very poor reflector of energy and can lead to an underestimate of a storm"s intensity.

Atmospheric conditions such a ducting. When ducting occurs, the radar beam is refracted into the ground (indicating stronger storms than what are actually occurring). However, a worse case is when subrefraction is occurring and the beam is overshooting the most intense regions of storms (indicating weaker storms than what are actually occurring).

Doppler radars that get out of calibration. The radar can become "hot" (indicating stronger storms than what are actually occurring) or "cold" (indicating weaker storms than what are actually occurring).

The radar beam spreads with distance meaning the most intense part of the storm"s reflected returns will be averaged with the weaker portions leading to an overall appearance of lower intensity.

When all returns from all elevation scans are compiled an image is created which takes the highest dBZ value from all elevations, called Composite Reflectivity. It is a picture of the strongest returns from all elevations.

When compared with Base Reflectivity, the Composite Reflectivity can reveal important storm structure features and intensity trends of storms. This is important because often during the development of strong to severe thunderstorms, rain-free areas (or areas with light rain) develop as a result of strong updrafts.

Yet, because it requires all elevation scans to be completed, unlike the Base Reflectivity being the first image created, Composite Reflectivity is the last image created in each volume scan.

This is important because often during the development of strong to severe thunderstorms, rain-free areas (or areas with light rain) develop as a result of strong updrafts.

In the loop (right)(below) it will change to the base reflectivity image from the same time as the composite view. The first thing you will notice about the composite image is there is much more "green" color near the radar, located at the center.

However, the base reflectivity image does not show that rain so it is probably not reaching the ground but evaporating as it falls from very high in the atmosphere.

Evidence of very strong updrafts (leading to the possibility of severe weather) can be seen when comparing the two images. At #1, the fuchsia colored region, visible on the composite image, is all but missing on the base reflectivity.

Remember the old adage "What goes up, must come down", using the color scale, this area is at 65 dBZ on the composite image. It is an area of concern as this is probably hail that has yet to fall. Some or most of the hail may melt before reaching the ground but at the very least, intense, blinding rain may be about to occur near this location.

The notches, at #2 and #3, show more rain supported by strong updrafts. Those locations require additional interrogation to determine what is taking place at these locations which will come from the velocity products.

One other note of caution, due to the time it takes to produce and transmit an image, all radar images show what HAS happened and NOT NECESSARILY WHAT IS happening.

Cepheid variable stars are important probes of stellar and cosmological astrophysics thanks to the Leavitt Law (Leavitt 1908). Not only are they essential tools for determining extragalactic distances, they are also crucial probes of stellar evolution theories. Cepheid pulsation periods are correlated to the mean density, hence changes in the mean density due to evolution yield changes in pulsation periods (Eddington 1918; Szabados 1983; Turner et al. 2006; Neilson et al. 2012b, 2016). This relation allows for the direct measurement of stellar evolution and testing state-of-the-art models of stellar evolution.

Turner et al. (2006) measured rates of period change for 196 galactic Cepheids and showed that the rate of period change indicates which crossing of the instability strip the Cepheid is on, which renders them useful tools for studying evolution. They showed that these rates of period change appear consistent with predictions from stellar evolution models. However, Neilson et al. (2012a, 2012b) went further and found that predictions of period change are inconsistent with that measured for the nearest Cepheid Polaris and that in general stellar evolution theory appears inconsistent with observations. Classical Cepheids evolve across the instability strip three times: the first is soon after the end of the main sequence as the star expands and cools, while the second and third crossing occur when the star transitions from having most energy generated by hydrogen shell-burning to helium core-burning and the end helium core-burning. During the first and third crossings the pulsation period increases, while during the second crossing the period decreases. By comparing the observed number of stars with positive period change and those with negative period change we can test stellar evolution. Neilson et al. (2012b) computed population synthesis models from a grid of stellar evolution tracks and found that from theory about 85% of Cepheids should have positive period change. The fraction from the Turner et al. (2006) sample is about 67%. The predicted fraction decreased to about 70% if the stellar models underwent enhanced mass loss during the Cepheid stages of evolution, suggesting evidence of Cepheid mass loss (Kervella et al. 2006; Marengo et al. 2010; Matthews et al. 2012).

On the other hand, Anderson et al. (2014) computed stellar evolution models of Cepheids using the Geneva code that included rotation and moderate convective core overshooting. They showed that when stars were born with about 50% of critical rotation the resulting Cepheid blue loop was a different shape and was more luminous than would be seen for a stellar evolution model with the same initial mass but no rotation. In terms of period change, they found that the rotating models have predicted rates of period change consistent with the results from Turner et al. (2006). Furthermore, Anderson et al. (2014) argued that rotation could help resolve the Cepheid mass discrepancy (Bono et al. 2006).

The Cepheid mass discrepancy is the difference between masses of Cepheids measured from stellar evolution modeling and from stellar pulsation measurements (Cox 1980). Caputo et al. (2005), Keller & Wood (2006), and Keller (2008) showed that the Cepheid mass discrepancy is about 10%–20%. As noted by Anderson et al. (2014, 2016), rotation is one possibility to solve the mass discrepancy, but Bono et al. (2006) suggested stellar mass loss, convective core overshooting, and missing opacities as well. The potential for missing opacities was deemed unlikely by Bono et al. (2006). Period change offers a powerful test of the role of these physical processes.

Convective core overshooting is a phenomenon that leads to a more massive stellar core at the end of a star"s main-sequence lifetime, thereby changing the mass–luminosity relation of Cepheids. In main-sequence stars with convective cores, convective eddies are assumed to rise toward the top of the convection zone with some acceleration and velocity. At the top of the convection zone the acceleration goes to zero but the eddy velocity does not. However, the layers above this boundary are not convectively unstable according to the Schwarzschild criteria, therefore in models the eddy does not penetrate the layers above the convective boundary. This is unphysical and to account for the fact that the eddies should rise above the convective boundary stellar evolution models include overshooting. This allows convective eddies to penetrate some distance above the core and mix material back into the core. In the Yoon & Langer (2005) code we use in this work, overshooting is input by the user as a fraction of the pressure scale height. This overshooting acts to extend the main-sequence lifetime and create a more massive post-main sequence core. Because of this convective core, overshooting is a possible solution to the mass discrepancy problem, as it leads to a more massive helium core (Huang & Weigert 1983) in the progenitor of the Cepheid, which will cause the Cepheid to be more luminous.

Convective core overshooting could resolve the Cepheid mass discrepancy to a point. If the discrepancy were the same for all Cepheids, then overshooting would be a likely solution. However, Keller (2008) found significant variation of the mass discrepancy for Galactic Cepheids, suggesting that overshooting on its own is insufficient. On the other hand, Neilson et al. (2011) determined that the combination of pulsation-driven mass loss and convective core overshooting could resolve the discrepancy as measured by Keller (2008).

Because there are a number of processes that can resolve the Cepheid mass discrepancy, we need alternative methods and observables to test those processes. In this work, we return to the analysis of Neilson et al. (2012a) to compare population synthesis models of Cepheid stellar evolution with rotation included, to determine how rotation impacts predicted rates of period change. In the next section, we discuss the stellar evolution model grid along with the included physics of rotation and overshooting in the models. In Section 3, we describe the population synthesis modeling using our stellar evolution tracks. We conclude with a discussion around the impact of our results and the role of stellar rotation in understanding the evolution of classical Cepheids.

Pool water testing can become so routine that simple mistakes could make your test results inaccurate. There are 12 pitfalls to avoid when testing your pool or spa water:

Where you gather your water sample from in a swimming pool matters. Avoid areas near return lines, steps, ladders and corners of the pool. These are locations in a pool where the pool chemistry is going to be different from the pool as a whole.

In order to get an accurate sample of your pool water, don’t draw the water from the surface because that is where the highest concentration of pollutants like oils and debris gather. The surface is also where evaporation is taking place and the interaction with the air can throw your results off. As a rule of thumb, an elbow deep depth between the shallow and deep ends of the pool is the sweet spot.

You pulled the sample from the perfect area and depth of the pool but didn’t test it right away. Life is full distractions – letting a sample sit too long gives it time to react with the air, sunlight, and even humidity. Commit to the process!

Even the slightest inaccuracy of a water sample can skew your test results. It may only be a few dozen drops of water, but too little or too much can tip the scales. Precision is key when it comes to achieving the best results possible. Hold your test vial at eye level and the bottom of the meniscus or curve of the water should be lined-up with the “Fill” level line.

You followed steps 1-4 perfectly, and added the perfect amount of reagent into the perfect amount of water and in all the excitement, didn’t swirl between drops. Take your time and mix the reagents thoroughly. Holding the comparator on the top between your thumb and forefinger, and rotate your wrist to swirl the sample within the test vial.

The best test kit money can buy can be rendered useless due to improper storage. The shelf life of pool test chemicals can be greatly impacted by hot and cold temps. Ideal storage temperatures are between 5° to 22°C (40° to 70°F). Bear in mind, that a constant fluctuation of temperature can also negatively impact the chemicals. Store pool test kits in a cool, dark place, and avoid prolonged exposure to the sun.

Colored Reagents Changing Colors: Taylor reagents 4, 8 and 11 are colored indicator solutions. Reagent 4 or pH Indicator is red, while reagent 8 or Total Alkalinity Indicator is green and Calcium reagent 11 is a blue color. If another color, you should replace the reagent.

Colored Reagents Staining Bottle: Taylor reagents 4, 8 and 11 should not stain the bottle in which they are contained, which indicates a separation of the test pigment. If the reagent bottle is stained, you should replace the reagent.

You can’t mix and match test kit reagent chemicals; this isn’t a matter of brand loyalty. Pool test kits vary by manufacturer and even the slightest variation of pool test chemicals strength and dropper orifice size can (everyone in unison) Render-Your-Test-Results-Inaccurate. Where have we heard that before? While we are on the topic of mixing and matching…

When you are done with a pool test chemical it is important to put the cap back on immediately. Not only does this help protect it from reacting with environmental variables it can prevent putting the wrong cap on the wrong bottle. Even if both caps are the same color (more reason not to delay), the chemicals under the caps are certainly not and a little bit of residue is enough to unravel the fabric of the universe – or at the very least, cross contaminate your reagents and you know that is a gateway to trouble.

Don’t touch the tip of the dropper bottles with your fingers. Exposure to these chemicals could irritate your skin and also the oils from your fingers can contaminate the drops. In addition to a clean reagent dropper bottle, thoroughly rinse out the test vials or optical chambers after testing. Lingering chemicals from a previous test is a surefire way to ruin your next test.

Hand-in-hand with removing your sunglasses is making sure you are not holding the optical chamber up to an artificial light source, or anything other than a white background (the purpose of the white rectangle, found in some test kits). A blue sky or blue water background can lead to a green pool when you misread test results.

1. Very High Chlorine levels (20 ppm+) can turn your pH sample test a variety of colors in the red/purple spectrum. You can however, add a few (1 – 3) drops of Taylor reagent #7, sodium thiosufate to the water, to remove the chlorine from the sample before adding the pH indicator or phenol red solution. You may still however obtain an inaccurate pH test, until the chlorine level is below 10 ppm.

2. Very Low Alkalinity levels (-50 ppm) can cause falsely higher pH test results, due to the relative pH level of the pH indicator solution, which is about 7.5. In a pool with low alkalinity levels, the pH of the test sample may change rapidly or “bounce” upwards, because of the addition of just 5 drops of the pH reagent, with a pH level of 7.5. This can raise your pH test result.

3. Out of Range Testing.Testing at the upper or lower limits of the test range can produce false test results. Between 7.0 and 8.0, you can discern the small changes and accurately test within that range. Below 7.0 and above 8.0 however, the test colors do not change reliably, and what may look like 9.0 is actually 8.4, or what appears as 6.6 is actually 5.8, for example. Make small additions or adjustments with pool pH chemicals, when pH is outside of the 7.0 – 8.0 range, to avoid overshooting the mark.

3. Very High Algaecide levels – quaternary ammonium algaecides (which is most pool algaecides), in very high concentrations in the pool can affect the alkalinity test, producing false low readings. Biguanides like Baquacil or Aqua Silk can also produce similar low alkalinity results, when levels are abnormally high.

1. High Chlorine levels, once again, high chlorine levels may be so high that the test sample “bleaches out” or turns a cloudy-clear color, after adding the reagents and swirling. In my low-range (0.25 – 2.5 ppm) K-2105 DPD test kit mentioned above, I can bleach out the test sample at less than 10 ppm, but the high-range K-2005 kit, which tests from 0.5-5.0 ppm, will go twice as high before the sample bleaches out. The problem is that high chlorine levels which don’t bleach out completely, will produce false low chlorine results. To measure very high chlorine, you can dilute the sample by filling the test vial half full of pool water, and half full of bottled water, and then double the test result.

2. Combined Chlorine levels, will begin to raise the Free Chlorine test result within 30 seconds. DPD test kits use 3 bottles to test for Free, Total and the difference between the two is combine chlorine, aka chloramines. After adding DPD #1 and DPD #2, take your test reading within 30 seconds, before the inhibitors stop working on the chloramines. Add #3 reagent also within 30 seconds, and if the sample turns noticeably darker, you have a measureable amount of combined chlorine in the pool. Rinse your DPD test vial completely after testing for free and total chlorine, any traces of DPD #3 reagent left can falsely raise chlorine test results.

You can’t do true backyard water analysis with test strips, sorry. They are too hard to discern, the ranges are too broad, and at best, can be 20% off the mark, one way or the other. The first pool water test blunder to avoid – are test strips.

I highly recommend the Taylor K-2005 test kit (and K-2006), and the ColorQ Pro7 by LaMotte, and greatly prefer the accuracy of liquid test kits over the convenience of test strips because, in pool chemistry, accuracy is king!