Wikipedia describes chlorine as... "the chemical element with atomic number 17 and symbol Cl. It is a halogen, found in the periodic table in group 17 (formerly VII, VIIa, or VIIb). As the chloride ion, which is part of common salt and other compounds, it is abundant in nature and necessary to most forms of life, including humans. In its elemental form (Cl2 or "dichlorine") under standard conditions, chlorine is a powerful oxidant and is used in bleaching and disinfectants, as well as an essential reagent in the chemical industry. As a common disinfectant, chlorine compounds are used in swimming pools to keep them clean and sanitary."

Most people assume chlorine testing only applies to pool water, but in reality, a person can find chlorine in many municipal water supplies, private wells, and in numerous manufacturing processes. Each application demands a different amount of chlorine and therefore each application requires a different testing method for chlorine concentrations.

DPD Test for Oxidizers... DPD -- The most common method for testing chlorine concentrations involves the use of a chemical known as DPD (N,N Diethyl-1,4 Phenylenediamine Sulfate) which comes in powder, tablet, reagentstrip, and liquid form. Each form of DPD has its advantages and disadvantages. 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. Click here for more information on DPD.

OTO Test for Oxidizers... OTO -- Commonly used in the pool & spa market for quite a long time, the addition of OTO (Orthotolidine) to water containing certain oxidizers, usually chlorine or bromine, will result in the formation of a color ranging from pale, light yellow to blood red. Although many test kits for pools and spas still pair OTO up with phenol red, a chemical used to measure pH, because of how simple the two chemicals make water testing, OTO tests only for total chlorine and provides semi-quantitative results at best. Most swimming pool and drinking water professionals agree that free chlorine levels matter much more than total chlorine levels when it comes to the sanitizing and disinfecting of water.

Water Testing and Water Quality Information... Looking for general information on water testing, water quality issues, and other topics related to the testing of water for drinking, swimming, industrial and other applications? Below you will find the most recent addition to the Water Testing Blog:    Request for Quote on DPD-1, 3 and 4 -- Today’s inquiry comes to us all the way from the United Kingdom. ‘Okello’ has interest in acquiring DPD test reagents for sanitizer/disinfectant level testing in water and asked, “I want the Quotation for DPD1-4″ At this time we carry 100 packs of DPD-1, DPD-3 and DPD-4 in the Water Testing Blog Test Kit Store. Differences [...]... 05/18/2012 | read the full article      Half of Students Cannot Identify the Atoms in Water — Scary! -- It frightened us to learn that nearly half of eighth graders all across the country cannot correctly identify the atoms in a water molecule. How can we expect today’s youth to care about the quality of water they ingest through out their lives if they can’t even figure out what atoms make up water in [...]... 05/17/2012 | read the full article      Pennsylvania Lab to Lose Accreditations for Violations and Pay $20,000 Fine -- Over and over again we tell people to make certain the water testing lab they choose has the proper accreditation… because we know for a fact that all labs do not perform equally! As an example, check out this article on a lab in Pennsylvania that failed to comply with established procedures and as a [...]... 05/14/2012 | read the full article      Dangerous Compounds Like Lead, BPA, Phthalates, Etc Found in Garden Hoses -- As much as all of us at Water Testing Blog would like to THINK the items we buy from the store do not contain potentially dangerous levels of things like lead, chemicals, etc., we certainly know BETTER than to allow ourselves to believe a lie like that. Question: Who besides us remembers the tragedy of [...]... 05/12/2012 | read the full article      Drinking Water Safety Tip After a Vacation Regarding Metals in Drinking Water -- Summer weather appears to have made its presence known in a few places already this year and many people have already started planning their annual vacations. While making those plans we ask that you add one small note at the bottom of your schedule or itinerary: Flush your home’s water lines for a bit when [...]... 05/11/2012 | read the full article   More Entries From WaterTestingBlog.Com