Chlorine Tests: Test Strips, Test Kits, Test Meters, and Replacement Reagents
Chlorine Chemical Symbol

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 -- 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. DPD & Chlorine in Water

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 -- 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. OTO and Phenol Red Test Kit for Total Chlorine and pH

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.

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:

-- Current weather forecast to a goo percentage of the United States: Hot Hot HOT... with a strong probability of HHHOOOTTT! With that said, everyone PLEASE take care to properly hydrate and occasionally cool off during the brutal heat assault man...... 07/19/2019 | read the full article
  -- Here's a question we hear often: "What is the simplest water filter I can buy?" We got asked that question, again, just the other day and it once again shocked us that someone would first think of simplicity rather than efficiency and effectivenes...... 07/17/2019 | read the full article
  -- In the mood for a... BATH? Who doesn't love a nice bath surrounded by warm water, your favorite scented soap, a few soft scented candles, some skin-abusing chlorine, and wait, WHAT? Kind of ruined the fantasy, right? Well fear not, friends, becaus...... 07/17/2019 | read the full article
  -- Warm weather woes... include swimming and frolicking in cool, refreshing swimming pools. Wait, what? How is that a PROBLEM?!?!? Well, I'll tell you: SOME people just DON'T understand a little 'bug' called Cryptosporidium, abbreviated as Crypto a...... 07/16/2019 | read the full article
  -- Over the weekend we got asked the following question about SenSafe John's Copper Test Strips (MPN 480042): "Is there a color key to match to on the bottle?" Yes, this product comes with a color chart on the outside of the bottle. To...... 07/15/2019 | read the full article


Liquid & Tablet Chlorine Test Kits   |   Electronic Chlorine Test Meters   |   Chlorine Test Strips   |   Chlorine Testing Information

[an error occurred while processing this directive]