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Buying tips that can help you get the best system for your money.

Tip #1: Silence is golden - but make sure the system runs 24/7. Noise does not purify water! The Type I system you buy should have a pump that continuously and silently recirculates water 24 hours a day, 7 days a week. Don’t be fooled by intermittent recirculation. It could be a ploy to cover up noisy pumps that were never intended to operate continuously, or pumps that heat up the water.

Aqua Solutions' history - coming up the hard way.

Aqua Solutions was founded as Solution Consultants, Inc., back in 1985. In those early days Aqua Solutions were not manufacturers. They were just integrators, who bundled together whatever brands of filtration and water purification equipment it took to best solve a customer’s problem. But before they could solve some of those customer’s problems, they had to solve the problems they were having with the water purification equipment they were trying to sell.

The RO+DI system can produce better quality water, at lower cost, than systems without built-in RO pretreatment. This laboratory water purification system is ideally suited for applications where the existing central RO, DI or distillation pretreatment system is either unreliable, overloaded (with regard to capacity), or nonexistent in a particular location.It is also suitable for applications where either space or funding limitations preclude purchasing separate RO and Type I DI systems.

It is difficult to measure the pH of type I ultra-pure water. It rapidly picks up contaminants that affect its pH and it has a low conductance, which causes instability in most pH meters unless they are specifically designed to work in ultra-pure water.

Fortunately, since the concentration of hydrogen ions in the water affects both pH and resistivity, the pH must lie within certain limits for a given resistivity reading. For example, if the resistivity is 10 Megohm-cm the pH must lie between 6.6 and 7.6. The pH of ultra-pure water can drop to 4.5 as it absorbs carbon dioxide from the atmosphere, but this does not mean that the water is now grossly contaminated; just a fraction of a ppm of CO2 will cause the pH to fall.

While many analytical procedures and instruments specify the type of reagent grade water that is needed (i.e., Type I, Type II, Type III or Type IV), just as many do not. As a “rule of thumb”, Type I Ultrapure water contains dissolved solids at the level of “a few parts per billion”, while Type II and Type III water contains dissolved solids at the level of about “1/ 8 to 1/2 part per million”, and Type IV water contains about 2.5 parts per million of dissolved solids.

Just pick up your phone and dial 1-800-458-2021, Ext. 21, 9AM - 4:30 PM Eastern time, and see how long it takes to get connected to a real LIVE person that can help you.

Then, call one of the other guys and see how long it takes.

When the CDC recently built a new 10-sotry R&D facility, they made a great discovery! They discorvered they could save some big money by eliminating the central DI lab water purification system and installing 80 compact, combination Reverse Osmosis + Type I DI systems instead! They saved big on capital, plumbing installation, and operating costs. And now, they're saving big on maintenance costs!

Water is one of the most commonly used reagents in the laboratory. It is an indispensable solvent for many uses like for preparation of buffers, media, liquid phases, gels and many more. Before water can be used in the laboratory it needs to be purified to meet certain specifications. by a lab water purification system. Water can contain a large amount of different contaminants that require different treatments to remove them. Particulates can be removed by different filtration systems that remove particulates based on their size. These can range from particles of 1mm size and larger (particle filtration) down to an effective pore size of 0.001 to 0.01 micron (nanofiltration) or reverse osmosis which removes large molecules selectively. Particulate filters can remove microbes like bacteria (0.2 -30 micron in size) or viruses (0.003 to 0.05 micron in size) and even endotoxin and RNAses based on the pore size of the filter in the system.

You are ready to buy a new glass washer for your lab, but you are unsure what water feed system to use? You probably already know what grade water you want to feed your glass washer. In most cases, except for special circumstances for very sensitive applications an ASTM Type II reagent grade water source will be sufficient for your lab glassware washer. ASTM Type II is defined as water that has greater than 1 MΩ/cm2 resistivity. Lower grades are not recommended for most application and Type I water rinses (>18 MΩ/cm2 might be necessary for especially sensitive application like HPLC and mass spectrometry. While there are several different ways for water purification like filtration, different kind of filtration, sterilization by UV radiation, adsorption by activated charcoal, to achieve the resistivity required for lab-grade water, the water need either to be distilled or deionized. Distillation requires the heating of water to the boiling point and collection of the condensate form the vapor.

Although it's not a water purification technology per se, continuous recirculation can significantly improve and maintain the ultimate water quality of any given laboratory water purification system.

Common sense tells us that stagnant water will degenerate in quality with time!

A 0.1 micron absolute-rated final filter cartridge or capsule, prevents suspended solids, particulate matter and bacteria from exiting a lab water purification system along with the purified water. The absolute rating means that nothing larger than 0.1 micron in diameter can pass through the filter.

This is essentially how beer and other liquids are "cold sterilized". The typical final filter capsule is manufactured per GMP standards from USP Class IV materials with no glues or surfactants, and is autoclavable, bubble point testable, and non-pyrogenic.

Ultrafiltration (UF) is similar to reverse osmosis, in that pressure is used to force water molecules through a porous membrane. However, the pores of a UF membrane are about 10 times larger in diameter than the pores of an RO membrane.

Because of this, the driving pressure can be much lower (25-50 psi), and any dissolved solids in the water will pass right through the membrane. The UF membrane removes suspended solids, colloids, bacteria, pyrogen, endotoxin, DNase and RNase from the water. In a laboratory water purification system, the ultrafilter is used to remove pyrogen, endotoxin, DNase and RNase.

Exposing water to 254 nanometer wavelength UV light can further purify it by sterilizing bacteria, thereby preventing their uncontrolled growth. 185 nanometer UV light oxidizes organic compounds, breaking them down into components such as CO2, which can then be removed by the ion exchange resins.

Since a 185 nanometer UV lamp actually produces light that is about 10% 185 nanometer and 90% 254 nanometer wavelength, it serves a dual purpose and also sterilizes any bacteria that pass through it. For design purposes, a UV oxidizer/sterilizer is usually located between two DI modules, so that the second DI module can polish the water back up to 18 megohm-cm, by removing the CO2, etc., generated by the oxidizing process.

A UV sterilizer is usually located after the final DI module, to ensure that bacteria cannot reproduce beyond that point. The use of a UV sterilizer after the final DI module, and before an ultrafilter module, can preclude the need for frequent, periodic chemical sanitization of the system.

Deionization (DI), a.k.a. ion exchange or demineralization, is a process whereby tap water is passed through charged cationic and anionic resin beds containing sites with available hydrogen (H+) and hydroxyl (OH- ) ions. As the ionized contaminants, such as Na+, Ca++, Mg++, Cl-, SO4--, and HCO3-, pass by the ionized sites, the cationic resin exchanges its H+ ion for the Na+ ion, and anionic resin exchanges its OH- ion for the Cl- ion, etc.

Each discipline specifies several other criteria for each Type (i.e., I, II, III, or IV). Needless to say, the three disciplines DO NOT AGREE on exactly what constitutes each Type!

For practical purposes:

* Type I ultrapure water usually means water that has 18 Megohm-cm or greater specific resistance, with other attributes such as bacterial count, TOC (total organic carbon), pyrogen and/or endotoxin and/or R-Nase and/or D-Nase levels, and specific ionic contaminant levels usually specified by the end user. It is essentially a given that this water meets the other criteria specified by CAP, ASTM and NCCLS.

Reverse Osmosis (RO) is aptly named. It actually reverses the natural osmotic process by using pressure to force pure water through a porous membrane. The membrane's pores are sized such that they allow pure water to pass through, while rejecting the contaminants in the water at up to 99% efficiency. In actual situations, the rates of rejection can vary from about 85% to 99% for various contaminants, based on the molecular weight or size of the contaminant and the operating conditions, which include pressure and temperature.

Activated carbon is the oldest, and probably the safest, form of liquid purification technology. It dates back to the earliest biblical recordings of beer and wine making, where it was used to improve the flavor. And, activated carbon is so safe, you can actually eat it in small quantities without any harmful effects!

Water contains a variety of impurities that can generally be classified into five major groups: Particulate matter.

• Microorganisms.
• Pyrogens, endotoxins, DNase and RNase.
• Dissolved non-ionized solids and gases.
• Dissolved ionized solids and gases.

Ultra-Pure Water, containing nothing but hydrogen and oxygen, has a specific resistance of 18.2 megohm-cm at 25 °C. Since conductance or conductivity is the reciprocal of resistance or resistivity, a cubic centimeter of pure water has a specific conductance of about 0.055 micromhos (i.e. microseimens) per cm at 25 °C. The conductance arises from the partial dissociation of pure water into hydrogen (H+) and hydroxyl (OH-) ions. Since conductivity is an increasing function of increasing water temperature, the temperature at which conductivity is measured MUST be taken into account. Most conductivity measuring devices simultaneously measure the water temperature, and compensate the conductivity reading as if it were taken at 25 °C.

Pure water is a commodity in many industries in particular in analytical and biologic laboratories. Laboratory grade water is defined by its resistivity, which is determined by the amount of ionic contaminations and by its Total Organic Carbon content (TOC). Resistivity of the water determines the water quality based on American Society for Testing and Material (ASTM) definitions. Many routine laboratory applications use ASTM Type II water that has a resistivity of >1MΩ/cm2 which corresponds to less than 500ppb total ionic contamination. More specialized applications in analytical chemistry and molecular and cell biology require water of ASTM Type I with a resistivity of >18 MΩ/cm2 which corresponds to about 1ppb total ionic contaminations in the water.