Finding Pure Water for Record Cleaning - very long
ABSTRACT—Finding pristine water for use in record cleaning is needlessly complicated by the utter lack of purity standards for water sold to consumers. This article explores the technical basis for setting suitable purity levels and provides a simple guideline for finding the right-quality water for your specific need in record cleaning.
SHORTCUT—If you have little patience for in-depth discussions, please proceed directly to the short(er) summary at the end. You may even want to skip this thread entirely if a little chemistry gives you a large headache. But I hope that you will stay with me as I plunge into the watery realm. I trust your time won’t be entirely wasted. After all, delving into minutiae is a big part of what makes our hobby—obsession?—so enjoyable. I must, however, apologize in advance for the didactic tone and verbosity that invariably permeate my writing. These are habits I’ve never been able to shake.
What kind of water should you use for record cleaning? This seems a laughably narrow issue at first. Most audiophiles instinctively seek the purest water they can find. But how pure is pure enough? And upon further reflection, could different record treatments require different water qualities? To further complicate matters, consumer products sold as distilled, de-ionized or reverse-osmosis water rarely if ever reveal their contaminant levels. So, how do you know which one is suitable for record cleaning?
I would like to offer some solutions. Nothing is easier than to fashion a list of recommended products, a safe approach on the Internet where instant gratification is expected—even demanded—and patience is a rare commodity. My preference is for a more deliberate and comprehensive approach that offers not just solutions but real understanding of the issues. I feel an obligation to buttress my views with detailed information that you can use not only to evaluate my conclusions but to make your own choices if so desired and to shed light on other water-related issues. That’s the long road—one that I hope you’ll take with me—with many questions to answer along the way. What contaminants are typically found in water? Which ones are harmful to record cleaning? Which purification methods are best at removing them? Which water is acceptable for rinsing records? How about diluting or mixing your own record cleaning fluid (RCF)? And finally, how do you estimate the purity of commercial water when the contaminant levels are not specified?
WHAT ARE TYPICAL WATER CONTAMINANTS?
I am not a polymath and I am familiar with water purity only insofar as this issue intersects with my research work in the lab. But I believe this knowledge is sufficient for our discussion. Water impurities may be divided into five categories: micro-biological contaminants, dissolved gases, soluble organic compounds, soluble minerals and solid particulates. Only the last three categories are really critical to record cleaning.
1) Micro-Biological Contaminants
Eliminating contaminants, such as viruses, bacteria and pyrogens (bacterial toxins causing fever in humans) is a must for water used in biology and pharmacy but not critical to chemistry laboratories or record cleaning. For your information, distillation and reverse osmosis (also called ultrafiltration) are two methods that will effectively remove biological contaminants from water.
2) Dissolved Gases
Some dissolved gases stay in the water after purification: e.g., excess chlorine from disinfection; carbon dioxide (CO2) dissolved in water as ions (H+, HCO3- and CO3--) of carbonic acid (H2CO3). Water may even harbor trace amounts of radon gas (!). Activated-carbon (AC) filtration is very effective at removing dissolved gases from water. De-ionization (DI) can remove dissolved CO2. Frequently, purified water exposed to air will re-dissolve CO2 and turn slightly acidic. But dissolved gases have little effect on Vinyl and are completely removed by vacuum.
3) Dissolved Organic Contaminants
Organic contaminants in water come from herbicides, pesticides, chlorination process (e.g, choroform) and industrial solvents (aromatic and polycyclic hydrocarbons, such as benzene; halogenated hydrocarbons, such as dichloroethane or trichloroethylene). These nasty byproducts of modern life left in the water are known collectively as total organic compounds (TOC). Distillation, de-ionization and reverse osmosis can partially remove TOC but activated-carbon filtration is by far the most efficient means of eliminating them, including the volatile fraction (VOC).
These organic contaminants are unhealthy or, at the very least, unpleasant in drinking water and certainly undesirable in laboratory water. But they are not the biggest problems for record cleaning, quantitatively or qualitatively. Their levels are low and the light fraction (VOC) readily comes off the Vinyl under vacuum. The organic residue on Vinyl is non- crystalline and therefore not as noisy as inorganic minerals. At any event, all record-cleaning fluids are “designed” to effectively remove these TOC regardless of their provenance—from the water or from the record.
4) Dissolved Inorganic Contaminants (Minerals)
Dissolved minerals, the predominant water contaminants, are dispersed in water as ions (charged particles). Sodium, calcium, magnesium, iron, aluminum, copper, arsenic, lead and mercury are examples of positive ions or cations; chloride, fluoride, sulfate, nitrate, bicarbonate and silicate are examples of negative ions or anions. This litany of ions in water are collectively called total dissolved solid (TDS) and their level is expressed in parts per million (ppm). Less TDS means low electrical conductivity for water or, inversely, high resistivity (in megohms. centimeter or Mcm), a quantitative measure of purity. De-ionization is by far the most effective methods for eradicating these dissolved minerals, closely followed by distillation. Reverse osmosis is less effective but capable of larger water throughput.
Dissolved minerals are the greatest source of record noise, especially silicates (from dissolved quartz and silica). As water evaporates, dissolved minerals are deposited on the Vinyl surface as hard, sharp-edged crystals creating the clicks and pops that can turn Vinyl sound into a real headache. While surfactant-based RCFs can tolerate some minerals—surfactants “bind” some of these ions, in particular polyvalent ions, such as calcium—alcohol-based RCF cannot and requires make-up water with the lowest TDS (highest resistivity). Record rinsing demands mineral-free water for the same reason.
5) Solid Particulates
Some particulates (sand, quartz, dust) are insoluble in water; they exist as sediments, solid suspensions, or colloidal suspensions, which are sub-micron particulates that can scatter light and make water appear hazy-blue (Tyndall light scattering). If imbedded in the Vinyl grooves, these particulates can cause very unpleasant clicks and pops, especially large particulates that act like giant boulders blocking the path of the stylus. Fortunately, distillation and reverse osmosis do an excellent job of removing these particulates. Purified waters are commonly micro-filtered to removes all particulates including colloids (0.22micron filter). Though solid particulate can be very harmful to records, they are usually—not always—absent from consumer water.
HOW EFFECTIVE ARE VARIOUS PURIFICATION METHODS?
Water is heated in a distiller or “still,” a term reminiscent of the Prohibition era. As it boils, water rises as steam leaving most impurities behind. The rising steam spirals through a cooling section where it condenses as “distilled water.” Distillation boasts the broadest capabilities of any water purification method. It can remove up to 99 percent of impurities from water including bacteria and pyrogens, particulates, heavy organics (boiling points above 100° C) and dissolved minerals (heavy metals and radio-nucleides included). The level of these impurities can reduced to a vanishing point by triple distillation. Without special setups, however, distilled water still contains CO2 and VOC that boil ahead of or along with the steam.
Dissolved CO2 and volatile VOC, especially those with similar boiling points to water’s, are contaminants that cannot be removed by simple distillation. Consequently, distilled water usually has an acidic pH of 4.5 to 5.0 and a water resistivity of 1 Mcm or lower. Special stills (with gas vents or fractionating columns) can remove VOC but activated-carbon filtration is a far better choice against these contaminants because it removes chlorine and radon gas as well and does all that at a much lower energy cost.
Effectiveness of Distillation
Biological contaminants (viruses, bacteria, pyrogens, cysts): Very Good
Dissolved gases (CO2, chlorine, radon): Poor
Soluble organics (except VOC): Good
Particulates (sand, dust): Very Good
Soluble minerals (salts, hardness, iron, heavy metals): Very Good
2) De-ionization (DI)
De-ionization employs acidic and basic resins (usually in a mixed bed) to eradicate ions from water. Cations (sodium, calcium) and anions (chloride, sulfate) from the water are tightly bound to the resins, which release H+ and OH- in exchange into the water. Do not confuse DI (mixed-bed H+/OH- resin) with water-softening (Na+ resin). While both process operate under the same principle—ion exchange—the latter merely replaces calcium and magnesium (water hardness) with sodium. DI can remove all dissolved minerals (including silicate), organic ions, as well as ionized gas (CO2, radon). It is the best method for removing dissolved minerals and thus tailored-made for record cleaning. It cannot, however, remove uncharged organics or biological contaminants, which are critical in drinking water but not in record-cleaning water. Filtration and micro-filtration must be used to remove solid particulates and colloids from DI water.
Commercial and laboratory DI units amazingly remove 99.9% of dissolved minerals from water in one pass. As dissolved CO2 and organic ions are also removed, de-ionized water routinely exceeds 1 Mcm in resistivity (better than single-distilled water). When reverse-osmosis water is used to feed a DI unit and other “polishing” units (activated- carbon filtration and micro-filtration), the final water reaches an extremely high purity (resistivity ~ 18.2 Mcm) and is essentially free of all contaminants.
Effectiveness of De-ionization
Biological contaminants (viruses, bacteria, pyrogens, cysts): Poor
Dissolved gases (CO2, chlorine, radon): Good
Soluble organics (charged ions only): Good
Particulates (sand, dust, colloids): Poor
Soluble minerals (salts, hardness, iron, heavy metals): Outstanding
3) Reverse-Osmosis (RO) or Ultrafiltration
Reverse osmosis, also called ultra-filtration, is a process that removes impurities by pressurizing water through a semi-permeable membrane (cellulose acetate or polyamide resins). Microscopic pores in the membrane allow water to pass through but retain most impurities, including very small ions. Suspended solid particulates are also retained by the membrane because of their large sizes. RO is capable of removing over 99% of viruses, bacteria and pyrogens. Typically, about 90% of charged particles (mineral and organic) are rejected by RO in a single pass and up to 98% in a double pass; this rejection is based on ionic size as well as ionic charge density. RO water is often also called de-ionized water creating much confusion for the chemically-challenged consumers. Organics and gases without charges are not effectively removed by RO.
Though RO does not reduce the impurities to the lowest level—at least not in one pass— this purification process is nearly as broad as distillation and far more energy-efficient. It can also handle larger throughput with less frequent regeneration than ion-exchange resins. RO unit is best used to pre-treat water that feeds DI or distillation; this arrangement dramatically enhances the ultimate water quality while increasing both the capacity and life of the purification system. An AC filter is often used upstream of an RO unit to extend its life by catching TOC that can rapidly clog an RO membrane.
Effectiveness of Reverse-Osmosis Filtration
Biological contaminants (viruses, bacteria, pyrogens, cysts): Very Good
Dissolved gases (chlorine only): Poor
Soluble organics (charged ions only): Good
Particulates (sand, dust, colloids): Outstanding
Soluble minerals (salts, hardness, iron, heavy metals): Very Good
4) Activated-Carbon Filtration (ACF)
Activated-carbon (AC) filtration is designed for the sole purpose of removing TOC from water. Highly porous carbon with huge surface area is produced by heating peanut shells or charcoal at extremely high temperatures in the absence of air. Activated carbon provides an abundance of sites for physical adsorption of organic contaminants.
ACF does only one thing but it does it very well: it removes from water all organic compounds (herbicide, pesticides, industrial solvents, chlorination byproducts, etc.). Large organic molecules are strongly held by multiple sites. Small organic molecules that fit within small AC pores are also detained. ACF removes excess chlorine but does not effectively remove viruses, bacteria, charged ions (sodium, calcium, nitrate, fluoride) or heavy metals (lead, mercury) except when a very specific type of AC filter is used.
Effectiveness of Activated-Carbon Filtration
Biological contaminants (viruses, bacteria, pyrogens, cysts): Poor
Dissolved gases (chlorine): Good
Dissolved organics (pesticides, industrial solvents): Outstanding
Particulates (sand, dust, colloids): Poor
Soluble minerals (salts, hardness, iron, heavy metals): Poor
5) Water Purification System: Multiple Methods for Ultimate Purity
It should be clear by now that each purification method has its strength and weaknesses. Distillation is the broadest and the most effectiveness method but has difficulties handling VOC and dissolved gases. RO is nearly as broad as distillation but less effective; it performs poorly with dissolved gases. DI excels at removing minerals (TDS) but performs poorly against micro-biological contaminants and particulates. Finally, ACF is by far the best method for removing organics (TOC) but is impotent against most other contaminants.
In practice, using a combination of well-chosen methods in the right sequence can boost the effectiveness of the purification system far beyond that of individual methods. To produce good record-cleaning water, distillation and de-ionization are the two most suitable methods (lowest levels of TDS). By themselves, however, neither method is sufficient to produce the water purity required for record cleaning. Both methods give better results when combined with RO and/or ACF to reduce TOC. And both methods benefit from micro-filtration, which helps eliminate particulates of all sizes down to sub-micron levels. The salient message bears repeating: combining purification steps dramatically reduces the impurity levels in the water. So, not all distilled or de-ionized waters are the same. You must pay special attention to the additional purification (polishing) steps that make a big difference in the quality of the final product.
WHAT ARE THE STANDARDS FOR WATER PURITY?
Are you surprised that there are no purity standards for water sold to consumers? You shouldn’t be. Companies often specify the “main” purification method and little else. We will learn how to estimate the purity of consumer water. But first, we must review the standards for reagent-grade water. Their relevance will become clear soon.
The most rigorous standards for water purity were established by the ASTM (American Society for Testing and Materials). Reagent waters are divided into Type-I, II, III and Type-IV grade based on resistivity (which reflects the TDS), TOC and the levels of three major minerals (sodium, chloride, silica). When low micro-biological levels are required, reagent-water is further subdivided into Type A, B and C with levels of bacteria and endotoxin specified. These sub-categories are not relevant to our applications. The top two grades, With very low limits on TDS and TOC, Type-I and Type-II water are used in laboratories and should be quite suitable for record cleaning.
Resistivity:.... 18 Meghom.cm minimum
Sodium:......... 1 ppm maximum
Chloride:....... 1 ppm maximum
Silica:.......... 3 ppm maximum
TOC:............ 50 ppm maximum
Type-I grade water is usually prepared by triple distillation or by single distillation followed by DI (to minimize TDS) and AC filtration (to minimize TOC) if necessary. Alternatively, in a continuous set up, RO water is used to feed a DI unit (mixed-bed ion-exchange resins) to achieve Type-I grade. Often, to ensure consistent quality, several purification stages are combined: coarse filtration, AC filtration, RO, and DI. In all cases, micro-filtration with 0.22-micron filter must be used. Type-I grade water is used in the semiconductor and pharmaceutical industries.
Type II Grade:
Resistivity:.... 1.0 Megohm.cm min.
Sodium:......... 5 ppm max.
Chloride:....... 5 ppm max.
Silica:.......... 3 ppm max.
TOC:............ 50 ppm max.
Type-II grade is the typical quality of single-distilled water. In practice, AC filtration, or RO or DI is often used to treat the water before distillation to achieve Type-II grade water consistently. As usual, MF with 0.22-micron filter must be used in all cases. Type-II grade water is suitable for most works in chemistry laboratories.
Resistivity:.... 4.0 Megohm.cm min.
Sodium:......... 10 ppm max.
Chloride:....... 10 ppm max.
Silica:.......... 500 ppm max.
TOC:............ 200 ppm max.
Type-III grade water is usually the product of a distillation, RO or DI, alone or combined, followed by a coarser MF using 0.45-micron filter. Though the resistivity is high, the silica content (mostly from colloidal silica suspensions smaller than 0.45 microns) is unacceptable for record cleaning. The 0.45-micron filter is used here instead of the 0.22-micron filter to significantly increase the water throughput and reduce the frequency of filter replacement with an unavoidable penalty on the silica level.
In all three grades of reagent water, the maximum level of silica is specified. This is important as fresh water (from underground aquifers, lakes and rivers) is usually loaded with silicates (dissolved silica) due to prolonged and intimate contact with the ground. Water also contains colloidal suspensions (sub-micron particulates) of insoluble silica particles so small they scatter lights and often make pure water appear hazy-blue. Poorly filtered water can contain over 500 ppm of silica, which can have an annoying effect on record noise as hard, sharp silica crystals can act like sand-paper on Vinyl. Despite its excellent resistivity, Type-III or IV water is not suitable for record cleaning, mostly because of high levels of silica.
A less rigorous, non-ASTM standard called “ultra-pure” water is sometimes used for a water of slightly lower and wider range of quality than Type-I water; individual ions are not specified:
Resistivity:.... 10 to 18 Megohm.cm
TDS:............. 10 ppm or less
TOC:............. 50 ppm or less
“Pure” water is also used for a water of similar but wider range of quality than Type-II grade without individual ions specified:
Resistivity:.... 1 to 10 Megohm.cm
TDS:............. 50 ppm or less
TOC:............. 50 ppm or less
BOOTSTRAPPING FOR PURE WATER
How can ASTM standards serve us? We have seen that Type-I and Type-II water are the higher-grade products reserved for laboratory work. Their ultra-low limits on TOC, TDS and silica (the terrible trio) perfectly suit record cleaning. We have seen that, to pass these standards, specific combinations of methods must be used to purify the water. If we can find the same combined methods on the labels of consumer products—e.g., distillation with ACF and MF, or DI with RO, ACF and MF—then we can reasonably assume that their impurity levels are commensurate with Type-I or Type-II grade. This bootstrapping approach is necessary in the absence of standards for consumer waters.
WHAT ARE LABORATORY-GRADE & REAGENT-GRADE WATER?
If you live in an area where there are testing laboratories—check the Yellow Pages—and if you ask nicely, you can get small quantities of laboratory water from these laboratories at no charge (bring your own container). Since it is not a hazardous chemical, you may also be able to order reagent-grade water from laboratory suppliers.
1) Reagent-Grade Water from Laboratories
Laboratories usually have water-purification systems that supply large quantities of purified water continuously. A typical system in a lab (e.g. Barnstead Easypure or Millipore Elix) uses tap water or de-ionized water as feed. The system consists of a pre-filter to remove coarse particulates, an AC filtration unit to remove organic materials (TOC), an RO and/or DI unit to remove ions (TDS), and finally a ceramic micro-filter to remove all particulates larger than 0.22 microns. A built-in meter continuously monitors the resistivity of the final product. Most systems can produce large volumes of Type-II water (resistivity > 1 megohm.cm) suitable for common chores in the lab or smaller volumes of Type-I water (resistivity >18 megohm.cm) which is used for all chemical tests. Both types of water are suitable for record cleaning though Type I is preferred. The huge advantage of laboratory-grade water is the quality insurance because the resistivity of the water produced is “constantly monitored.”
2) Reagent-Grade Water for Special Applications
Laboratory suppliers (Sigma-Aldrich, Fisher Scientific, Sargent-Welch) sell reagent-grade water (de-ionized or distilled; Type-I) in convenient amber-glass bottles for about $6 to $7 per gallon. These products are “certified” to have low levels TOC and TDS (lot analysis) and are therefore more reliable than consumer products.
Special applications in the laboratory such as HPLC, Ion Chromatography, GC- and LC Mass Spec, UV Spectroscopy, semi-conductor work, etc., require water of special quality. Such product obviously must have very high resistivity ( > 18 Mcm) and very low TOC and TDS. The limits of specific contaminants are set very low as well depending on the application. This type of water is expensive (about $50 per gallon). It is typically sold in one-gallon bottle (or boxes of four one-gallon bottles) and available only through laboratory suppliers. The pricey water is perfect for audiophiles who want only the best but far exceeds any real need in record cleaning.
WHAT PURITY LEVEL(S) DO YOU NEED FOR RECORD CLEANING?
1) Making/Diluting Surfactant-Based RCF
Surprisingly, and contrary to claims by some companies, surfactant-based RCF does not require the purest of water. Most distilled and de-ionized waters that meet the Pure-Water or Type-II standard should work just fine. The reasons are straightforward. First, the largest source of contaminant from a surfactant-based RCF is…the surfactant itself. At 1000 to 5000 ppm, the surfactant level swamps that of all water contaminants combined—even low-quality distilled or DI water contains far less than 100 ppm TDS, which is 10 to 500 times below the amount of surfactant in the RCF. Second, the surfactant itself will easily remove contaminants from the water through solubilization, emulsification, foaming and specific binding. After all, that’s what a surfactant does. If it can’t deal with traces of water contaminants, then it will be completely impotent against record contaminants. Mind you, using Type-I, ultra-pure or triple-distilled water to mix or dilute surfactant-based RCF does no harm but it does unnecessarily raise the cost and the false expectation of higher effectiveness.
2) Making/Diluting Alcohol-Based RCF
I am referring here to a record cleaner that uses only alcohol—usually isopropyl alcohol or IPA—diluted in pure water without surfactant or other additives. This type of RCF requires the purest water in its makeup. Here is the reason. While effective against organic contaminants, alcohol (unlike surfactant) has a limited ability to remove dissolved minerals or suspended solids, the worse contaminants for LPs. For this reason, the water used with an alcohol-based RCF must have very low TDS. If you are making your own alcohol-based RCF, I would strongly recommend using Type-I water. Also keep in mind that alcohol can easily leach plasticizers from the wrong kind of plastic container, so it’s is imperative that you use a glass or polycarbonate bottle for storage (see discussion on water storage below).
3) Rinsing Water
Rinsing helps remove RCF leftover from the Vinyl after vacuuming (adsorption film and evaporation residue). I strongly recommend repeated rinsing after using most RCFs. Only very pure water should be used for obvious reason. As very little surfactant or alcohol (or other surface-active agents) is left to aid in removing contaminants during rinsing, the rinse water itself should contain as little contaminant as possible to avoid re-contaminating the cleaned Vinyl. As in the case of alcohol-based RCF, I recommend Type-I or ultra-pure water (< 10 ppm TDS; < 50 ppm TOC). Specialty (e.g., HPLC) water would be great if you can get it and can afford it but it is not a must.
Now, some final words about rinsing. After using an alcohol-based RCF, rinsing is a good idea but not absolutely necessary unless the RCF also contains other additives (usually a little surfactant). Surfactant-based RCF usually requires multiple rinsing to remove the dried surfactant left on the Vinyl that can be noisy. Manufacturers of some surfactant-based RCFs that contain a lubricant or preserver—whatever that function may be—do not recommend rinsing as the left-over additive helps dampen surfactant noise. I find that a single rinse, however, can remove most of the surfactant and still leave much of the less water-soluble additive intact. The choice is yours.
WHERE AND HOW TO BUY COMMERCIAL WATER?
Many commercial products are sold under the name of the “main” purification method. Unfortunately—or fortunately—not all distilled, de-ionized or RO waters are the same. As seen earlier, no single purification method can remove all the contaminants from the water with equal efficiency. For this reasons, consumer water is usually subjected to several purification steps. Unfortunately the levels of various contaminants and the overall resistivity are not disclosed for commercial products. One solution for consumers is to look for the purification steps, which are often listed on the label. Knowing these steps, you can estimate the purity level of a product with a reasonable certainty based on the ASTM standards. Look for distillation or DI as the main purification method. The combination of either method with ACF and MF should produce Type-II water. The combination of distillation or DI with RO, ACF and MF steps should produce Type-I water. There is no absolute guaranty of purity—only actual water analysis can do that—but this bootstrapping approach is far safer than blind faith in the commercial appellations (distilled water, RO water, etc.) which amounts to dousing for pure water.
1) Commercial Distilled Water
Many grocery stores and specialty-food stores sell distilled water in one-gallon plastic containers. By now, you should not be surprised that these products are not all the same. Below are actual commercial products I found in my neighborhood stores. The brand names are shown only as examples and should not be misconstrued an endorsement or indictment of the products.
Distilled Water (with Ozonation) – Generic store brands (e.g., Remarkable’s; Albertson’s) give little information about their products, which are usually sold in one-gallon plastic jugs. We can safely assume that this is single-distilled water which is possibly subjected to micro-filtration but no other polishing steps. This drinking water is usually replenished with oxygen by ozonation. The purity is undoubtedly below Type-II or “pure water” grade (TDS > 50 ppm; TOC > 50 ppm). But the silica level should be low thanks to distillation. This water is adequate for making up your own surfactant-based RCF but nothing else. The cost is usually between $0.80 and $1.00 per gallon (often on sale for $0.50 per gallon). Since the cost of higher-grade water is about the same, my suggestion is to buy this water only if you can’t find anything better.
Distilled Water with Activated-Carbon Filtration, Micro-Filtration and Ozonation – I found this basic combination of purification processes on most regional/national brands of distilled water (e.g., Ozarka) and on some health-food store brands (e.g., 365 from Whole Food). AC filtration reduces the TOC below that of regular distilled water while micro-filtration ensures that the water is free of particulates. These products will have the purity of Type-II grade water or “pure water” (TDS ~ 10 to 50 ppm; TOC < 50 ppm). Sold in one-gallon plastic containers, their cost varies between $1 and $1.20 per gallon. This water is safe for most record cleaning applications, though Type-I water is preferred for rinsing and mixing alcohol-based RCF.
Distilled Water with Active-Carbon Filtration, Reverse Osmosis, De-ionization, Micro-Filtration and Ozonation – I found this outstanding combination of purification processes on a few brands of distilled water sold in specialty-food stores (e.g., Rain Fresh sold by Whole Food). RO water, already low in TDS and TOC is used to feed the distiller, ensuring very low TDS and TOC; these contaminants are further reduced by DI (ion-exchange resin) and AC filtration. Finally, micro-filtration removes particulates from the water. The entire process takes 24(!) steps. This water is equivalent to Type- I water (TDS < 10 ppm; TOC < 50 ppm). It is excellent for record cleaning. The cost is about $2 per gallon with $2 cost or deposit for the inert polycarbonate container.
2) Commercial De-Ionized/Reverse-Osmosis Water
DI water (from ion-exchange resins or RO filtration) is far less common commercially than distilled water. Fortunately, many specialty-food stores are starting to have in-house purification systems to produce excellent DI and RO water at very low cost. Some of these products are comparable to Type I and Type II reagent water.
For example, Whole Food offers tripled filtered water with RO or RO and DI combination. The triple filtration includes micro-filtration and AC filtration, which knocks down solid particulates and TOC respectively to very low levels. RO reduces 90 to 98% of TDS and TOC from the water that feeds the DI unit, which further reduces the mineral content to vanishing levels (99.9% removal of TDS). Periodic analyses show the TDS to be far below detectable level (< 20 ppm). Common ions like sodium and chloride are below 1 ppm and most other ions are undetectable (below a few parts per billion or ppb). Individual organic compounds are below detectable levels as well (ppb) bringing the TOC to well below 20 ppm. This de-ionized water meets or exceeds Type-I grade. It is an outstanding product for record cleaning and very affordable at 39 cents per gallon—of course, at this price, you bring your own polycarbonate container. And make sure you use the right combination of levers—not intuitively obvious—to get both RO and DI.
3) Storage Containers
This important topic is too often overlooked. It is pointless to spend time, effort and money acquiring high-purity water only to re-contaminate it with improper storage. Unfortunately, most distilled waters sold in grocery store come in plastic containers that will slowly leach plasticizers or other chemicals (dioxin), which we can easily detect by the “plastic smell” in the water—our nose is an amazing chemical detector, but that’s another story for another time. Some plastic containers use caps improperly lined with paper or cork which are additional sources of contamination. Some use metal parts in the dispensing spout which will corrode and contaminate the water as well. Avoid them.
The best choice for long-term storage is a one-gallon glass bottle with amber glass that offers UV protection in addition to being completely inert (ordinary glass bottle tends to leach out silicate with long-term storage). Such glass bottle is usually fitted with a hard phenolic screw cap lined with a Teflon disc to prevent re-contamination during use. These bottles may be hard to get as they are sold only by chemical suppliers.
Polycarbonate containers for pure-water storage are easier to find and by far the best choice among plastic containers. They will not leach chemicals into the water which will always remain odorless. It also has a very smooth surface which makes cleaning a breeze. This clear (bluish) plastic is impact-resistant to boot. You can tell what kind of plastic a container is made of by looking up the “Recycle Code” on the bottom of the container. It is the number within a triangle. Look for # 7 for polycarbonate. Below is a list of Recycle Codes for common household plastics:
1......PET.....Polyethylene teraphthalate (clear)
2......HDPE....High-density polyethylene (transluscent)
3......PVC.....Polyvinyl chloride (opaque)
4......LDPE....Low-density polyethylene (transluscent)
6......PS......Polystyrene (opaque; hard)
7......PC......Polycarbonate (clear; blue)
Once again, look for caps with inert lining and do not the tempted by complicated dispensing spouts with PVC, rubber and/or metal parts that will invariably corrode or degrade to contaminate the water in the long run. Before use, all containers must be meticulously washed with a mild detergent and repeatedly rinsed with tap water and finally with the pure water to be stored. A one-gallon polycarbonate container usually costs about $2 to $5. You can also use a one-gallon PC container—PC stands for polycarbonate, not politically correct—from local suppliers of pure water to health-food store (e.g. Rain Fresh) for a nominal deposit ($2).
4) Best Buy
By far the best-buy in purified water is the triple filtered/ RO/DI water found in some health-food stores at around $0.39 per gallon in bulk (!)—I used my own PC container. You can use this Type-I water for ALL applications in record cleaning. Its quality exceeds that of most bottled distilled waters. Just make sure that the purification unit is properly maintained (fresh MF filters, RO membrane and DI cartridge) and that the results of periodic water analysis are posted. Once again, make sure you pull the right levers to get both RO and DI and not just RO.
OVERVIEW—My goal is to help you find high-purity water for record cleaning among consumer products, which totally lack any purity standards. My recommendation is to look for very specific purification steps on the product labels. Waters produced by these methods meet or exceed the standards for reagent-grade water typically used in laboratories. Such products should be suitable for record cleaning.
CONTAMINANTS & PURIFICATIONS—I have identified three types of water contaminants that are harmful to LPs: dissolved organic compounds (ppm of TOC), dissolved minerals (ppm of TDS) and solid particulates (suspensions; ppm of silica). I have also highlighted the relative strength of purification methods. Distillation: broad purification with high effectiveness. De-ionization (DI): best removal of TDS. Reverse-Osmosis (RO) Filtration: broad and rapid purification. Activated-Carbon Filtration (ACF): best removal of organics. Micro-Filtration (MF): best removal of suspended particulates (0.22-micron filter). One thing is abundantly clear: multiple purification steps are required to remove all water contaminants harmful to record cleaning.
READ THE LABEL—Based on their low impurity limits (TOC, TDS and silica), I have concluded that Type-I (or “ultra-pure”) water and Type-II (or “pure”) water, normally reserved for laboratory uses, are suitable for record-cleaning applications. I have also pointed out that a) the combination of distillation or DI with ACF and MF produces Type-II water and b) the combination of distillation or DI with RO (pre-treatment) plus ACF and MF steps produces Type-I water. These are the specific purification steps that we seek on the labels of consumer water.
REAGENT-GRADE WATER—As a consumer, you may have access reagent water which are “certified” as Type-I or Type-II water. Testing laboratories in your area may let you have small quantities of this water free of charge—check your yellow pages and bring your own container. Chemical suppliers, such as Fisher Scientific, Sargent-Welch or Sigma-Aldrich sell reagent-grade water (Type-I) at $6 to $7 per gallon in inert (amber) glass bottles certified by lot analysis. Water for special laboratory applications, such as HPLC, is ultra pure, very expensive (about $50 per gallon) and seems like an overkill for record cleaning. If you do not have access to laboratory water, you can still find consumer products that will meet Type-I and Type-II reagent-grade standards.
UNSUITABLE WATER—Consumer water produced with a “single” purification step should not be used except as the last resort. Unfortunately, distilled water sold in most grocery stores is produced by single distillation without additional purification steps except for MF (ozonation oxygenates the water but does not purify it). Water purified by RO alone usually does not meet Type-I or Type-II specs either unless multiple passes and additional MF are specified. For in-store RO water, check analysis before buying.
SUITABLE WATER—Type-II grade or “pure” water is suitable for mixing or diluting surfactant-base RCF. It is probably also safe for alcohol-base RCF and record rinsing, although I prefer Type-I water for these applications (without surfactant) to minimize re-contaminating the records with dissolved minerals. Distilled water treated with ACF and MF (e.g., Ozarka or 365) will meet or exceed Type-II or “pure” water specs (TDS ~ 10 to 50 ppm; TOC < 50 ppm; silica < 3 ppm). It is sold in one-gallon plastic containers—to be replaced—at a modest cost of $1 to $1.20 per gallon.
PREFERRED WATER—Type-I grade or “ultra-pure” water (TDS < 10 ppm; TOC < 50 ppm; silica < 3ppm) is best for all record cleaning applications. There are several sources of this product for consumers. Distilled water further purified with ACF, RO, DI, and MF is an outstanding choice often found in specialty-food stores (e.g., Rain Fresh sold by Whole Food). The cost is $2 per gallon (with $2 deposit for the excellent polycarbonate container). De-ionized water (very low in TDS) is harder to find. Some specialty-food stores have in-house units that produce tripled filtered water (coarse filtration, ACF & MF) treated with combined RO and DI. The purity levels meet or exceed Type-I specs making this water an outstanding product for all applications in record cleaning. At 40 cents per gallon, it is a bargain to boot—at this price, I did not mind bringing my own container. Inquire about the age of various cartridges before buying.
STORAGE—Pure water should always be stored in inert glass bottle or polycarbonate container (#7) to avoid re-contamination with plasticizers or dioxin from common plastics. Most consumer waters are sold in high-density polyethylene (#2) or polyethylene teraphthalate (#1) containers. They should be replaced. Before use, all storage containers must be thoroughly cleaned and rinsed. Use proper aps (no cork or paper lining). With the right-quality water and proper container for storage, you should be able to mix your own RCF, dilute commercial products or rinse your records in complete safety and with excellent results.
PARTING WORDS—If you have stuck with me all the way through this discussion, I commend you for your exceptional stamina and thank you for your time and patience. If you get here via the shortcut, your interest however limited is still much appreciated. Either way, I hope that I have given you sufficient information to help you select and find the high-purity water that you need in record cleaning. If, in addition, I have given you a reasonable understanding of the water issues as well, I consider my goal fulfilled beyond expectations even if your ultimate choices differ from mine.