Janet wrote in and asked…

I need to buy Dpd Tablets and I have not found a supplier nor a Manufacturer to buy from.

Kindly Link me with Dpd Tablets Manufacturers who can supply me.

We thank you very much, Janet, for your inquiry and suggest you take a look at the material below, as it will lead you to what you seek:

For those of you interested in learning more about DPD and its uses, please refer to an earlier posting entitled What id DPD?.

National Stock Number (NSN) for “Chlorine Test Tablet” — 6550012191061 and 6550014257957

We recently received a number of request from Water Testing Blog readers to post a list of popular water quality topics so that they could keep tabs on ‘hot topics’ more easily. Not wanting to disappoint, we have decided to do this on a semi-regular basis.

Below you will find the most popular Water Testing Blog entries for the month of July 2009:

• Free Chlorine and Total Chlorine: In this chlorine-related water quality blog posting we discussed why some chlorine testing products such as Pool Check Test Strips work exceptionally well for swimming pools and spas, but do not offer the correct chlorine detection levels required for drinking water.

• Free, Total & Combined Chlorine: In this chlorine-related water quality testing blog entry we dicussed the differences between free chlorine, total chlorine, and combine chlorine as well as methods to test for each one.

• Dirty Pool Water Can Make You Sick: The title pretty mucha says it all. Just as with drinking water, failing to test pool water can allow dangerous forms of bacteria to grow, flourish, and possibly make a person sick. Remember: 1 in 5 American Adults Admits to Peeing in the Pool. Yuck!

• www.pool-water-test-kits.com: In this posting we brought this pool water test kits to your attention. It’s a fast, easy way to find the pool/spa testing supplies you need to keep your water crystal clear, safe, and enjoyable.

• Free Water Hardness Test Strips: Here we pointed people to Morton Salt Company and Diamond Salt Company web sites where they could order free water hardness test strips.

• DPD Tablets for Chlorine Testing: We always stress the importance of accurate chlorine testing and in this post we provided links to a web site where readers could find replacement DPD tablets and replacement DPD powder for their chlorine/bromine test kits.

• Water Filters for Hikers & Campers: For all those who enjoy going for long walks in the woods, camping in the mountains, mountain biking, or just having clean, safe drinking water to drink when away from home, we provided links to personal water filtration devices and systems from the Katadyne Company.

• Hardness Grains per Gallon vs. Parts per Million: Once again, the name says it all. What more can we say about this posting dealing with water hardness measurement scales.

• Chlorine Filters for Garden Hoses: One would think people already know that the same chlorinated water they filter in their homes goes in their gardens, too, but apparently not… so we provided links to water filters for garden hoses.

• www.pool-water-testing.com: Here we simply brought a site dedicated to testing pool water to the spotlight. Not much more to say really… other than go test your pool often!

With temperatures soaring to record and near record highs all across the United States, it comes as no surprise to us that we have received numerous questions pertaining to the proper treatment of green swimming pool water, smelly swimming pool water… and some water that would make the average sewer worker vomit.

Therefore we have located yet another online source for Pool Water Testing and Pool Chemical Supplies. Below you will find quick links to various pool testing supplies, pool chemicals, pool shock treatments and other items such as automatic chemical feeders for swimming pools.

Just as with your drinking water, though, nothing beats a professional water test if you have reason to suspect that harmful bacteria or harmful levels of contaminants have entered your pool water.

With all the posts we’ve written about the importance of testing chlorine levels in drinking water, we seem to have forgotten that a lot of people have test kits already and simply need replacement dpd tablets. The links below will take you to a site where you can pick up replacement dpd tablets and DPD powder for the Taylor brand of water test kits for pools and spas.

Several membsers of the Water Testing Blog staff have spoken with members of the military, both currently enlisted and recently discharged, and found out that some soldiers do not have access to simple, efficient tools they can use to test potential drinking water while deployed in foregin countries.

In most cases they carry packets of sanitizing/disinfecting tablets which they can use to put into their canteens to kill off bacteria, but what about lead, arsenic, cyanide and other items which can EASILY render an entire unit inoperable and take them away from their assigned duties?

Thankfully US Army, Navy, Air Force, and Marine Corps medical units deployed around the globe now have the ability to make use of simple water quality test kits which give them the ability to read basic water quality parameters quickly and easily.

Arsenic in Water and Soil: Arsenic Quick^TM

Bacteria in Water: Bacteria Check

Chlorine Residual (Free): SenSafe^TM Free Chlorine Water Check

Chlorine Residual (Total): SenSafe^TM Total Chlorine Water Check

Cyanide in Water: Cyanide ReagentStrip^TM

DPD-1 and DPD-4 (Chlorine Testing): eXact DPD ReagentStrips^TM

Lead in Water: Lead in Water Test Kit

Multi Parameter (6 Parameters): Well Water Check

Multi Parameter (11 Parameters): Well Driller Standard Water Test Kit

Multi Parameter (13 Parameters): COMPLETE Water Test Kit

Multi Parameter (15 Parameters): Water Quality Test Kit

Most of us know how badly we feel after ‘a night on the town’ filled with margaritas, martinis, cocktails and body shots because of dehydration. Now try to imagine how our soldiers must feel after a few MONTHS in the desert wearing full combat gear.

Safe drinking water means safer soldiers.

One of the most widely used testing methods for free and total chlorine makes use of something known as ‘DPD’ which stands for N,N Diethyl-1,4 Phenylenediamine Sulfate. The addition of DPD to water samples containing oxidizers such as free chlorine, bromine, iodine, chlorine dioxide and/or permanganate results in the formation of a reddish tint to the water whose intensity directly relates to the amount of oxidizer(s) present in the water sample.

At low oxidizer concentrations water samples turn a slight shade of pink in the presence of DPD and at higher oxidizer concentrations the sample will turn blood-red orange. In extremely high concentrations of oxidizers, as in above 10 ppm, the sample will turn blood-red and then go crystal clear due to the bleaching effect of the oxidizer(s) it contains.

Other oxidizers such as ozone and total chlorine do not react directly with DPD and require the addition of a compound known as Potassium Iodide (KI) before they will react with DPD.

• DPD-1 — Used to test oxidizer levels in water samples containing free chlorine, bromine, iodine, chlorine dioxide and/or permanganate.
• DPD-3 — Useless on its own, but when added to samples already containing DPD-1 and free chlorine, total chlorine, bromine, iodine, chlorine dioxide, permanganate and/or ozone, pink through blood-red color development will occur in the sample.
• DPD-4 — The combination of DPD-1 (N,N Diethyl-1,4 Phenylenediamine Sulfate) and DPD-3 (KI) to samples containing free chlorine, total chlorine, bromine, iodine, chlorine dioxide, permanganate and/or ozone will result in pink through blood-red color development in the sample. Simply put, DPD-1 + DPD-3 = DPD-4.

DPD comes in various forms, the most common of which include tablets, powder pillows, liquids and ReagentStrips^TM. Each works equally well when used correctly and may typically be interchanged with one another, though all do have their pros and cons.

• Tablets: One of the cheapest forms of DPD available and has a very long shelf-life. Difficult to break apart and dissolve in cold or hard water samples and may leave suspended solids floating around in samples.
• Powder Pillows: Inexpensive form of DPD. Difficult to dissolve in cold or hard water samples and may leave suspended solids floating around in samples. Users also complain of ‘annoyance value’ associated with having to tear the foil pillows open and pour the DPD powder into the sample vials. Not well-suited for outdoor testing.
• Liquids: Shorter shelf-life and much more unstable than other forms of DPD, considered ‘messy’ by many users, but also probably the expensive form of DPD.
• ReagentStrips^TM: Convenient delivery method for DPD, rarely leaves undissolved solids in samples regardless of temperature or hardness, decent shelf-life, and available in bottles of 50 or individually wrapped tests (excellent for field work).

While many test protocols call only for a visual verification of chlorine levels in water determined through the use of DPD testing methods, many others require the use of a digital chlorine analyzer and DPD testing methods. Below please find an EPA Compliant meter which make use of DPD chemistry for chlorine concentration determination:

• eXact Micro 7+ Water Quality Testing Meter — EPA Compliant for free and total chlorine when used in conjunction with a DPD-based reagent system.  Handheld multi-parameter water quality testing meter.  IP67 waterproof rating and the unit floats. Made from recyclable parts and uses 60% less reagent than devices using 10 mL samples.

Per the request of several men and women currently serving in the United States Armed Forces and other branches of the Unites States Government, we will begin posting possible alternate products for popular (established) NSN’s (National Stock Numbers) related to water quality testing.

NSN: 6550012191061, 6550014257957 — Chlorine Test Tablets

“DPD REAGENT TEST TABLETS FOR CHLORINE ANALYSIS. PACKAGED IN INCREMENTS OF 100. LAMOTTE.”

Alternatives:

• DPD 1, 3 and 4 ReagentStrips — Faster and more convenient than traditional DPD test tablets. No MSDS required. Safe to use on production room floors of food processing facilities. EPA Compliant testing method. Packaged in bottles of 50 or individually wrapped in foil packs. Costs as low as 8 cents a test.

eXact^® Strip DPD ReagentStrips

Note: We have found that the products suggested above meet or exceed the specifications of the original NSN (National Stock Number) item. This does not mean, though, that you may substitute them in place of the item on a Government Contract. We provided the above information as possible sources of water quality testing products for consideration in future Contracts/Bids only.

Per the request of several men and women currently serving in the United States Armed Forces and other branches of the United States Government, we will begin posting possible alternate products for popular (established) NSN’s (National Stock Numbers) related to water quality testing.

NSN:  6630014574027 — Digital Chlorine Analyzer

“RUGGED COLORIMETER WITH ADVANCED OPTICAL SYSTEM THAT ELIMINATES STRAY LIGHT ERROR; DIGITAL READOUT DIRECTLY BETWEEN 0-4 PPM WITH A PLUS/MINUS 2% PHOTOMETRIC ACCURACY; READING STABILITY WITHIN 1% OF FINAL VALUE WITHIN 5 SECONDS; MEETS EPA REQUIREMENTS 330.5 FOR DPD COLORIMETER; DIMENSIONS: 7 IN. BY 5 IN. BY 4.5 IN.”

Alternate Product Suggestions:

• eXact Micro 7+ Water Quality Testing Meter — EPA Compliant for free and total chlorine when used in conjunction with a DPD-based reagent system.  Handheld multi-parameter water quality testing meter.  IP67 waterproof rating and the unit floats. Made from recyclable parts and uses 60% less reagent than devices using 10 mL samples.
• Palintest Chlorometer 1000 Water Quality Testing Meter — Highly portable and EPA Compliant for free and total chlorine when used in conjunction with a DPD-based reagent system.
• Palintest Bromometer Duo Water Quality Testing Meter — Highly portable and EPA Compliant for free and total chlorine when used in conjunction with a DPD-based reagent system.  Also tests for bromine.

Note: We have found that the products suggested above meet or exceed the specifications of the original NSN item.  This does not mean, though, that they may be substituted in place the item on a Government Contract.  We provided the above information as possible sources of water quality testing products for consideration in future Contracts/Bids only.

While many water professionals worry about getting chlorine into water and establishing a chlorine residual, other water professionals worry about removing chlorine from water.

• Example 1: Before water from a well can pass a coliform bacteria test at a certified laboratory and get approved for human consumption it must test as having absolutely no chlorine residual in it.

• Example 2: Federal, State and Local Environmental Laws/Regulations prohibit the discharging of highly chlorinated water from a wastewater treatment facility or from any other water processing facility. Chlorine, even in low concentrations, poses a serious danger to the ecosystem and the releasing of too large an amount into environment can wipe out the area’s vegetation and animal life very rapidly.

What Type of Chlorine Should One Test For?

Typically speaking, when concerned about the amount of chlorine residual in the discharge from any sort of wastewater treatment facility, most people check for total chlorine. Testing solely for free chlorine would not suffice for environmental purposes because combined chlorine, also called chloramines, can still have harmful effects on the environment despite not having the as great an oxidation potential as free chlorine.

How Can One Test for Low Levels of Total Chlorine?

Test Strips: Quick, easy and cost effective. Test strip methods for chlorine concentration determination offer extreme amounts of convenience and require little or no technical training. Just dip the strip and compare the color of the test area to a color chart. (total chlorine, ultra low total chlorine)

DPD: Typically used in conjunction with a colorimeter, DPD methods for chlorine concentration determination give more precise results than most visual methods, but as stated, they typically require the use of instrumentation (see DPD ReagentStrips, eXact EZ, Chlorometer 1000, eXact Micro 7+). For environmental compliance monitoring and reporting purposes, most government bodies require the use of an EPA Compliant DPD testing method.

Titrations: A time consuming method which typically uses DPD in liquid form and requires a certain amount of laboratory skills. Not very practical for field work. Uses liquid reagents which have a shorter shelf-life than comparable powders, tablets, etc.

A reagent (chemical) known affectionately as DPD has reigned supreme as the ‘best’ way to test for the presence of free or total chlorine in water for quite a while now. What most folks don’t know is that someone has FINALLY found a way to make using DPD cost-effective and convenient.

DPD ReagentStrips: Looks like a test strip, but functions like a totally convenient way to precisely administer measured amounts of DPD into a 10 mL water sample. All the reagents, buffers and indicators come neatly impregnated on the pads at the end of an ergonomic PVC strip. Simply swish the pads around in your sample for 20 seconds, remove the strip, throw it away, and read your sample in your preferred colorimeter. DPD ReagentStrips fall under the guidelines of EPA Compliance and may be used in place of all other DPD methods. . . and they don’t require MSDS.

Also, at approximately $0.08 per test (USD), the DPD ReagentStrips make staying in strict compliance with EPA guidelines for chlorine detection quite affordable.

Previously, DPD came in one of three forms: powder pillow, tablet or liquid. Each has its benefits. . . and each has its downfalls.

Powder Pillow: The most popular form of DPD. Precise amounts of the reagent come in single-dose foil ‘pouches’ that the user tears open and pours into their sample. Sounds like a great idea, yes, but try using these things in a ‘wet’ or windy environment. Anyone who works in the field will know what that means. MSDS required.

Liquid DPD: Cheap as can be, but with that inexpensive price comes an incredibly short shelf-life compared to other DPD delivery systems. MSDS required.

DPD Tablets: Very inexpensive, very stable. Great way to deliver exact amounts of DPD into samples, except for one small problem: DPD tablets do not dissolve smoothly or easily in cold or hard water. In either type of water, DPD tablets typically leave undissolved solids floating in the sample and in colorimeters, these can lead to erroneous readings.

Fast Dissolving DPD Tablets: Same as above, but they can leave other materials in the sample: Elements of the binding agent which held the tablets together prior to immersion in the sample.

So as you can see, older methods of DPD delivery have met their match. For more information and even to receive free samples of the DPD ReagentStrips, check out the Industrial Test Systems, Inc. web site. This is one free and total chlorine testing innovation you don’t want to miss out on!

UPDATE: For certain free chlorine testing applications, states now have the ability to approve the use of EPA Approved SenSafe(tm) Free Chlorine Check test strips. Please consult with your State and/or Local Health Departments to see if your State has approved their use. Benefits include faster test times and no monochloramine interference.