And we thank YOU, Colina, and your boss for all your business!  Regarding the two products, both detect concentrations of free chlorine in water samples and as you know, the  SenSafe 481026 product detects up to 6ppm and the WaterWorks 480023 product detects up to 25ppm.

Dilution method

To use the strips you have, you will need to use a dilution method.  Below you will find two examples of how to properly dilute a sample and back calculate the free chlorine concentration.

NOTE:  Make sure you use distilled or other water known to possess a zero chlorine concentration for dilutions.

• 1 part distilled water + 1 part water sample ... Perform a test using a test strip ... If you get a reading on the strip that matches one in the strip's color chart range, multiply that reading by (2) two to get the actual concentration of chlorine in your water sample.
• 2 parts distilled water + 1 part water sample ... Perform a test using a test strip ... If you get a reading on the strip that matches one in the strip's color chart range, multiply that reading by (3) three to get the actual concentration of chlorine in your water sample.

As a general rule we always suggest having the proper tool for any testing job.  Therefore we carry WaterWorks & SenSafe brands of water test strips for chlorine testing with varying detection ranges:

• Ultra low, low, high, and ultra high range free & total chlorine testing products

SenSafe Free Chlorine Water Check Detects 0 - 6 ppm

SenSafe Total Chlorine Test Strips Detect 0 - 10ppm

WaterWorks 2 Free & Total Chlorine Test Strips

Thank you for the chlorine testing question, MK.  At this time we have a High Range Free Chlorine product (MPN 480022) with a high detection limit of 120ppm, an Ultra High Range Free Chlorine product (MPN 480024) with a high detection limit of 750ppm, and an Ultra High Range II Free Chlorine product (MPN 480124) with a high detection limit of 2,000ppm.

If you need to test for Total Chlorine, regrettably we do not have a product that detects 120ppm total chlorine.  We do, however, have a High Range Total Chlorine product (MPN 480033) that detects up to 80ppm.  With a 50-50 dilution of the sample and appropriate 2x multiplier for the result detected by this product you could probably make it work -- assuming the level of total chlorine did not exceed 160ppm.

If simply drained into the streets the water winds up in storm drains which lead sometimes lead to local waterways where the chlorine could cause serious harm to aquatic life.

Draining pool water into sanitary sewer systems — the same ones that handle waste water and toilet water — could cause those systems to get backed up since many do not have the ability to handle large volumes of water.

So… How should I dispose of pool water?

From what we have read, environmental experts and department of public works employees suggest allowing the pool water’s chlorine level to dissipate as much as possible before releasing water into the environment or storm water systems. Make sure to keep the pool water circulating with the pool’s pump/filter during the dissipation process since doing so should aid in making the chlorine dissipation process go a little faster.

How will I know when the chlorine level drops close to zero?

Simple dip-and-read test strips for TOTAL chlorine, not free chlorine, work well and your basic 5-drop OTO pool water test kits work well, too.

Total Chlorine High Range
Test Strips

If you have a need to test for total chlorine levels (free chlorine + combined chlorine) in the range of 0 to 80 ppm then the Total Chlorine HR (High Range) water quality test strips will definitely come in handy. Sold in bottles of 50 tests, this product makes total chlorine testing in the field, in the lab, and just about anywhere a fast, easy process.

• Detection Range: 0, 5, 10, 20, 30, 40, 60, 80 ppm (mg/L)
• Total Test Time of Less Than 40 Seconds
• Manufacturer Part Number: 480033
• Made in the United States by Industrial Test Systems, Inc.
• Total Chlorine HR Test Strips require no powders to mix, tablets to crush, drops to add/count, or glass ampuoles to break.

What is the MCL (Maximum Contaminant Level) for Chlorine?

In municipal water systems the US Environmental Protection Agency has stated that a water treatment facility must take immediate action to reduce free and/or total chlorine levels in excess of 4 ppm (mg/L).

How Does the Total Chlorine HR Compare to DPD Test Methods?

Unlike DPD test methods for higher (than 10ppm) concentrations of total chlorine which require test personnel to perform dilutions before testing samples, the High Range Total Chlorine Test Strips allow for immediate, on-the-spot testing of water samples.

Why Do DPD Test Methods Require Dilution(s) of Samples?

When testing water samples containing more than 8 to 10 ppm of total chlorine either as free chlorine or combined chlorine the chemical indicator DPD ‘bleaches out’ and becomes clear. Therefore a sample must get diluted prior to testing to make certain the total chlorine concentration does not approach 8 parts per million.

The Total Chlorine High Range test procedure does not require dilution for samples containing more than 8 or 10 ppm chlorine since its chemical indicator can endure and continue to function properly in the presence of elevated chlorine levels.

Moral of the Story?

If you need to test for higher levels of total chlorine than traditional DPD methods allow, and you want to do it quickly and accurately, the WaterWorks Total Chlorine High Range test strip product will most certainly come in handy.

We all know that improperly balanced pool water can cause eye irritation due to a low/high pH, low/high alkalinity, and/or too high a chlorine count, but what about a properly balanced swimming pool? Does that water cause harm in any way?

According to the article,

• The human eye has a natural protective barrier over it that helps protect it from infection by bacteria, parasites, etc. Chlorinated water removes that thin layer temporarily.
   
• Swimming pools disinfected with chlorine may have the correct amount of chlorine in them to effectively ward off ‘bugs’, as the author called them, but that same chlorine loses some of its efficacy if the pH or alkalinity has drifted out of acceptable range.
   
• The amount of bacteria and other unwanted pool water contaminants introduced by a high bather load (aka: lots of people in the pool at one time) may temporarily overwhelm the chlorine concentration’s ability to neutralize threats to swimmers — especially their eyes whose protective tear layers have temporarily gotten washed away.
   
• Contact lens wearers may want to pay special attention to pool water water quality and possibly take extra steps to flush out their eyes after a swim. Putting lenses back in one’s eyes possibly without rinsing traces of pool water out first may allow infectious, or simply unwanted, bacteria and/or parasites to get trapped between a contact lens and a person’s eye… where it could breed, grow and basically cause problems.
   
• The good news? A properly sized and well-fitting set of goggles can really help minimize an eyeball’s exposure to tear film erasing chlorinated water and opportunistic ‘critters’ that sometimes lurk in pool water — like, for example (and we did not know this, by the way)… ‘pink eye’.

The article also mentioned something in passing: Carrying a pool water test kit with you to the pool. Sure you may look like a science geek or some sort of paranoid parent at the neighborhood pool, but if the water turns out to not possess the right chemicals to keep you and your family safe, well, we think a little embarrassment goes a long way!

Moral of the story?

Swimming pool water, even in the best circumstances, temporarily wipes away a vital protective barrier that our eyes rely upon to keep them ‘safe’. Therefore it stands to reason that we ought to make certain our pool water has the right balance of water chemistry (testing pool water helps with this!) and use properly fitting eye protection whenever we go for a swim!

Oh, and… one more thing before we go: At the beginning of each swimming season and each time a pool gets filled up or topped off with fresh water from a well or spigot, make sure to test the quality of the fill water for things like metals, hardness, alkalinity, pH, etc.

Why? Because just like in the world of computer programming, “Garbage in, garbage out!”

For your pool that means if you add water that has some water quality issues to begin with, then your pool water will have water quality issues, too.

Although both manufactured by Industrial Test Systems, Inc., a US based company in South Carolina, the DPD-1 ReagentStrip and SenSafe Free Chlorine Water Check products test for free chlorine residual in very different ways.

The chart below will explain the differences and similarities between the two free chlorine residual test methods:

	DPD-1 ReagentStrips™	SenSafe™ Free Chlorine Water Check
Detects:	Free Chlorine Residual (and Other Oxidizers Normally Tested Using DPD-1 Chemistry)	Free Chlorine Residual
Test Procedure Overview:	Liberarting of DPD-1 Reagents Off Reagent Pads Into 10mL Sample and Checking Chlorine Concentration Visually by Color Comparator or Electronically Using a Colorimeter	Immersion of Test Strip in Water Sample, Removal of Test Strip After Specified Period of Time, and Visual Comparison of Developed Color in Test Area to a Color Chart
Detection Range:	0-6ppm	0-6ppm
Accuracy & Precision:	Depends on the Method Used to Interpret the Developed Color in the 10mL Sample. Visual Methods Will Have Less Precision Than Meters	0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.2, 1.5, 2, 2.6, 4, 6 ppm (mg/L)
Certifications & Compliance:	DPD Testing as Specified in 4500-CL G Check w/ Your Local Health Department for Final Word on Compliance	USEPA Approved Test Method for Free Chlorine Read the EPA Letter   View EPA Approved methods   Check w/ Your Local Health Department for Final Word on Compliance
Number of Tests:	100 Tests per Package	50 Tests per Package
Benefits:	Cleaner to Use Than DPD-1 Powders (i.e. DPD-1 Powder Pillows)   Dissolves Easier Than DPD-1 Tablets   Longer Shelf-Life Than DPD Liquid Reagents   No Undissolved Solids When Testing in Cold Water (5ºC)   Requires No MSDS	Safe for Use on Most Production Floors   Requires No Specialized Testing Knowledge   No Expensive Meter (Colorimeter)   Designed to Resist Monochloramine Interference   Requires No MSDS
Per Unit Cost:	$15.99 per Package of 100 Tests	$15.99 per Bottle of 50 Tests

As always, if monitoring free chlorine residual for reporting and/or compliance monitoring we suggest contacting your local health inspector before switching to a different chlorine testing method.

Although seemingly counter-intuitive, many methods approved on a Federal level may not have attained acceptance, yet, on a State or Local level.

In the water business testing for free chlorine happens quite frequently (as Scott just said)… and we know of two ways to make that task easier:

• DPD ReagentStrips — If you use DPD-1 to test for free chlorine residual, then undoubtedly you do so using DPD in powder or tablet form. Both methods work, but DPD-1 ReagentStrips make testing for free chlorine residual in water a faster and easier process while staying in compliance with 4500-CL G. Simply insert a DPD-1 ReagentStrip into a 10mL water sample, move it back and forth (liberated required DPD chemistry off of reagent pads), and read visually or with your favorite meter.
   
• SenSafe™ Free Chlorine Water Check — In the original recommendation letter from the USEPA, dated October 2003: “We believe that the ITS test strips will provide the regulatory community with a valuable option for monitoring free chlorine levels in drinking water.” This method bears USEPA Approval for in drinking water applications.

While both testing methods make free chlorine residual testing much easier without losing accuracy, we highly suggest check with your State and Local inspectors first before using either product for compliance monitoring… because as you know (probably better than we do!), sometimes State/Local regulation changes do not always keep up with Federal Regulation changes.

Ann asked, “Hi. I work in the food and beverage industry and our our most recent health inspector told us we need to have a way to test for 800ppm or greater free chlorine residual in our washing solutions. Do you carry anything for that? I saw the ones that go up to 120ppm but I need higher. Thanks.”

Well, Ann, we do actually carry a product for testing higher concentrations of free chlorine in water: Free Chlorine Check Ultra High Range II tests up to 2,000ppm free chlorine and does so in about a minute.

Below you will find the color chart for the :

Color Chart for Free Chlorine Check Ultra High Range II

As you can see, this high range free chlorine test strip product has a low detection level of 25ppm and a high detection level of 2,000ppm.

What’s the deal w/ the sanitizing & disinfection solution labels?

The manufacturer’s of this product, Industrial Test Systems, originally created this product to meet a need in North Carolina. Because of several unfortunate incidents where young children in daycare and childcare facilities came in contact with disinfecting and/or sanitizing solutions mixed way too strong, laws were enacted that required licensed daycare and childcare facilities in North Carolina to test the concentrations of their ‘bleach water’ on a daily basis.

Childcare and daycare facilities in North Carolina have authorization to use the Free Chlorine Check Ultra High Range II test strip product for the purpose of testing disinfecting and sanitizing solutions.

Note: Different states have different laws governing what constitutes a properly mixed sanitizing or disinfecting solution and different industries will also have different requirements. Check with your local health department or health inspector before deciding on the concentrations you will use!

Looking for the “The Childcare Kit – Part No: 480124-3K” ?

If so, then you already know it includes the following…

• (3) Bottles of 100 Tests… for a Total of 300 Tests
• (1) Tablespoon Measuring Tool
• (1) 1/4 Cup Measuring Tool
• (1) Sanitizer Preparation Method

… and you can purchase The Childcare Kit – Part No: 480124-3K in the Water Test Kit Store.

‘TomToo’ very recently — as in a few minutes ago — asked about chlorine testing and which chlorine test he should use:

“Saw your chlorine sale announcement and have a question. The water in our beach house stinks really bad of chlorine when we first get there and we want to test to make sure it’s safe to use but you have free and total chlorine strips. How do you know which to use?”

Thanks for your inquiry, TomToo, and believe us when we say others share your confusion when it comes to knowing which type of chlorine they need to test for.

Lucky for you, though, we have simple answer if your concern deals only with worrying about having too much chlorine in the water. You should test for total chlorine.

The USEPA set the Maximum Contaminant Level for chlorine in drinking water at 4 ppm (parts per million) and that number takes into account ALL of the chlorine in a water sample, meaning both free and combined chlorine.

Moral of the story?

If you need to know the FULL amount of chlorine in a drinking water sample, testing for total chlorine makes the most sense.

Whether testing drinking water at home, process water used in an industrial application, or wastewater for its chlorine before discharge into the environment, we feel quite certain that at least one of the chlorine test strip products above will come in handy — and this weekend you can save money when buying them!

As always, if you have any questions, please do not hesitate to ask! You may reach us easily using our Contact Us Form…. and yes we work on the weekends. 🙂

Have a great weekend, everyone, and don’t forget to stay hydrated!