While the average person does not have a need to for chlorine levels much above 3 to 5 parts per million, and even then they would typically only need to do so to make sure their swimming pools had a sufficient amount of free chlorine, but other folks have the need to test for free chlorine levels in excess of 25 or 50 parts per million on a regular basis. Below we will list a few of the places where you might expect to see a need for high range free chlorine testing.

Fruit & Vegetable Processing

After fresh produce leaves the fields it travels to a processing facility where it typically gets washed with a solution containing some sort of sanitizer such as chlorine, ozone, etc. In cases where the produce processing plant uses chlorine employees must make sure the rinse water contains a certain amount of free chlorine after it has passed over the fruit/vegetables.

Levels of free chlorine drop with an increase in biological load (contamination) and the rinse water having free chlorine left after use indicates that the produce no longer contains biological contamination on its surfaces.

Childcare Facilities

State laws require that childcare facilities clean their surfaces with properly mixed sanitizing and disinfecting solutions that contain an appropriate concentration of sanitizing or disinfecting chemicals. In many cases these facilities use chlorine bleach solutions for cleaning purposes.

As a general rule these solutions must contain anywhere from 50 to 200 parts per million free chlorine for sanitizing solutions and anywhere from 500 to 800 parts per million free chlorine for disinfecting solutions. In case like this the Waterworks High Range Free Chlorine Test Strips will not work because they have an upper detection limit of only 120 parts per million free chlorine, but WaterWorks Free Chlorine Check Ultra High II has an upper detection limit of 2,000 parts per million free chlorine and works well in this application.

Some states leave it up to individual childcare facilities to determine testing frequency of sanitizing and disinfecting solutions while other states, like North Carolina for example, have strict laws dictating how often childcare facilities must perform testing.

As of January 1, 2006, all licensed, non-in-home daycare centers in the State of North Carolina had to have the ability to test the chlorine bleach content in both their sanitizing and their disinfecting solutions. Previously the law stated that they had to test only the chlorine concentration in their sanitizing solutions. ( source )

If interested in purchasing a test kit for testing sanitizing & disinfecting solutions in a childcare facility, you can find them readily available on the Filters Fast web site.

Water Lines and Water Mains

Before a water line can go into service for the first time or go back into service after a breakage or leak has gotten repaired technicians must flush (burn) the lines with water containing a high concentration of free chlorine to clean out any and biological contaminants. Typically the technicians must test the discharge water periodically until the free chlorine level remains constant at a high level for a set amount of time.

Waterworks High Range Free Chlorine Test Strips work very well for this application.

Product-specific information about Waterworks High Range Free Chlorine Test Strips:

• Testing requires just 32 seconds
• Each bottle contains 50 ready-to-use tests
• Color chart has easily distinguished color blocks at 1, 5, 10, 20, 40, 80, 120 ppm
• No harmful chemicals or reagents to handle

Looking for a way to lower the amount of free chlorine and chloramines in the water you use in the garden… but don’t want the hassle of installing a complicated water filter?

If so, then we suggest you consider the Green Knight Hydroponic Dechlorinating Filter.

Functioning as an easily installed inline filter, the Green Knight screws right onto the average 3/4″ garden hose and promotes healthy plant growth by effectively reducing and/or removing potentially harmful chlorine from the water and also contains quartz crystals which aid plants’ absorption of vital nutrients.

Rainshow’r Green Knight uses a polyester pre-filter to catch sediment and then allows water to pass through 2 pounds of specially blended KDF55, 2 ounces of quartz crystal, and a final polishing stage which contains KDF73 filament media.

This product also comes with a sturdy 3-foot vinyl hose so that people can reap the benefits of the chlorine filter near the spigot/faucet w/o having to wrestle with a full-length garden hose. This works out well for rinsing off metal tools, washing mud off of dogs, etc.

Oh, and we learned something new while researching this product: People have found that reducing chlorine levels in rinse and wash water can greatly extend the life and luster of organic carnuba wax jobs on cars, boats, RV’s, etc.

Specific product details of the Rainshow’r Green Knight:

• Testing has shown that the unit removes 85% – 90% of Free Available Chlorine (FAC)
• Testing has shown that the unit also reduces chloramine concentrations by 65% – 75%
• Life expectancy: 30,000 gallons of source water assuming ‘average’ chlorine concentrations
• Suggested flow rate: Approximately 2 ppm
• Temperature rating: From 40F up to 110F
• Maximum pressure rating: 100 psi
• Freezing will cause irreparable damage to the unit, as will not running water through the unit at least twice a month after its first use.

Will the Rainshow’r Green Knight work as a drinking water filter?

Rainshow’r, the manufacturer of Green Knight Hydroponic Dechlorinating Filter designed this product for use in the garden and for outdoor applications, not for use a device to make water potable.

It lacks sufficient filter media capable of removing particulate matter and other contaminants such as organic chemicals, heavy metals (lead, iron, copper, mercury, etc.) and bacteria from source water.

While the idea of a shower head changing colors in response to a change in water temperature sounds kind of amusing, we think people ought to consider installing a shower head that will improve the quality of their shower water rather than the lighting in their shower stall.

Again, we find the following ‘technology’ rather cool… but somewhat superficial in the grand scheme of things.

You got your skin burned in the hot shower due to a mistake of turning up the temperature control too high as you couldn’t see the reading on the control knob clearly. So, you’ll need a better gadget that would tell you in a more prominent way that the water is burning hot. Here comes a color changing illuminated shower head, which changes color according to the temperature of the water. When you’re increasing the temperature of the water, the color will change from white when it’s cold, to blue, then purple and finally the hot red.

The color changing illuminated shower head features a temperature-sensitive color-changing LED. The shower head needs neither battery nor external power to run. All it depends is the water that runs through it. Installation is easy, just unscrew your current shower head and screw this one on. ( source )

Really cool looking shower colors may do a lot to set the mood for some things, like, um… Well, never mind that. Let’s just focus on the idea that shower heads designed to remove chlorine, excessive water hardness, or other water impurities make a lot of sense.

Note: WaterSafe makes a test kit to test both chlorine and water hardness. Details here.

We’d like to thank “Trinity” for asking the following question about trihalomethane levels in drinking water:

“In school we recently learned that chlorine added to drinking water by water treatment facilities reacts with organic contaminants in the water and forms harmful compounds called trihalomethanes. Does the EPA have a guidleine which limits the amount of trihalomethanes are considered safe?” — Trinity in Washington

First of all, we want to clarify something in Trinity’s question: Not all forms of chlorine added by water treatment facilities will cause trihalomethanes to form. Adding ‘free chlorine’ to water containing organinc contaminants will result in the formation of thrihalomethanes while adding ‘combined chlorine’, also referred to as chloramines, to water containing organic contaminants will not.

Unsure of the difference between free chlorine and total chlorine? The following Water Testing Blog postings will help:

• Free Chlorine, Combined Chlorine, Total Chlorine
• Free, Combined and Total Chlorine Re-Visited
• Testing Chlorine Levels — Drinking Water vs. Pool Water

Getting back to Trinity’s question, though, prior to 2004 the EPA set the maximum contaminant level (MCL) for trihalomethanes in drinking water at 100 parts per billion (ppb). In 2004 the EPA lowered the MCl for trihalomethanes in drinking water to 80 ppb. ( source )

Wanna’ hear a joke? What do you get when you cross chlorine with a fish tank? Dead fish!

Whether first starting out w/ a new aquarium or adding water to an existing aquarium, you must add water that contains as close to 0% total chlorine as possible — or your fish will die. For an explanation of the difference between free and total chlorine, please refer to an earlier blog entry entitled “Free, Combined and Total Chlorine Re-Visited“.

It goes without saying that you will want to your the source water for TOTAL chlorine, and not just free chlorine because ALL forms of chlorine can prove fatal to aquatic life even in small amounts.

You may use test strips, liquid test kits and/or a water testing meter. The exact testing method does not matter in so long as you trust the results you get from your testing. Keep in mind that your fishes’ lives depend upon that reading so choose your testing method carefully!

Several years ago researchers (we don’t recall from where) announced similar findings. Their research focused more on chloramine gas, a product of the reaction between free chlorine and organic contaminants such as sweat, body oils, etc. Additionally, the previous research also focused more on indoor pools where the chloramine gas could more easily build up as a result of poor ventilation.

The results of this more recent study, which broadened its focus to include children who swam in outdoor pools, indicate that children exposed to chlorinated pool water stand a much greater chance of developing allergies and asthma than children who swam in pools using alternate sanitizers such as silver/copper ionizers, which use far less chlorine.

MONDAY, Sept. 14 (HealthDay News) — Swimming in pools disinfected with chlorine may increase the odds that a child will develop asthma or allergies, new research suggests.

The study found that teenagers who spent more than 1,000 hours swimming in chlorinated pools, either indoors or outdoors, had more than eight times the risk of having asthma than did teens who primarily swam in pools using a copper-silver disinfecting method.

“Chlorinated pool attendance has a very significant impact on the prevalence of allergic diseases in the studied population,” said lead author Alfred Bernard, a professor of toxicology and research director at Catholic University of Louvain in Brussels, Belgium. ( source )

Does this mean all pool owners with chlorinated ought to run out into their backyards, drain their pools, and/or toss in a few pounds of chlorine neutralizer? ABSOLUTELY NOT!

Thus far the evidence indicates that proper usage of chlorine as a pool water disinfectant remains safe. The problems start, it seems, when chlorine levels get ‘too high’ in the water and when chlorine gases build up in the air above and around swimming pools.

“When used properly, [chlorine] is an efficient and safe disinfectant for swimming pools. However, when too much chlorine is added to water or builds up in the air of indoor pools, there is unavoidably some irritation of the organs of the bather in contact with the water and air,” he explained. “There is now increasing evidence that these irritating effects may be detrimental to the airways of regular swimmers, especially the children who are the most vulnerable and the most frequent attendees of chlorinated pools.” ( source )

So what can the average pool owner do to minimize the risks presented by their chlorinated pool? Simple: Test chlorine levels, and other vital water parameters, often and make sure not to use more chlorine than necessary to keep the water properly disinfected.

Bernard said that if you have a backyard pool, you should use as little chlorine as you can to safely disinfect the pool. He said that many people over chlorinate their pools to get clear blue water. But, he said, “chlorine is a disinfectant, not a cleaning agent.” ( source )

Indoor pool owners need to follow the preceding advice AND make sure their pool enclosure area has proper ventilation. Water in indoor pools typically has a higher temperature and thus tends to evaporate and also give off chlorine gas at a faster rate than cooler water.

“How can I test the chlorine level in my swimming pool?”

Swiiming pool test kits come in three basic forms, for the most part: Liquid Test Kits, Test Strips, and Pool Testing Meters.

After reading this article you may find yourself thinking, “I will switch to a copper-silver ionizer and say ‘goodbye’ to chlorine forever!” Sorry, but that last part will most likely not happen.

Many copper-silver ionizer pool water systems suggest maintaining low residual levels of free chlorine in pool water. Often times the suggested free chlorine levels will fall below the detection level of most test strips, liquid test kits and even some meters.

To monitor such low levels of free chlorine in pool water we suggest the Pool Check Low Chlorine 3-in-1 Test Strip which can detect free chlorine levels as low as 0.05 ppm.

All of us at Water Testing Blog already KNOW the dangers of releasing chlorine into the environment and applaud the California State Legislators for going after the organizations responsible for discharging water with higher than acceptable levels of chlorine from their facilities.

SONORA – The State Water Resources Control Board says in a proposed order that the Central Valley Regional Water Quality Control Board disregarded excessive chlorine being discharged into Woods Creek from a Sonora sewage treatment plant and also inappropriately increased the amount of chlorine that Sonora and Jamestown government agencies were allowed to discharge into the creek.

The proposed order the state board issued this week would require the regional board to revise its pollution permit for the treatment plant that serves the two cities to bring chlorine discharges within legal limits.

Woods Creek flows into Don Pedro Reservoir, a popular fishing area and a tributary to the Tuolumne River. The order points out that even extremely low concentrations of chlorine are damaging to fish populations. ( source )

Government regulations restrict the amount of chlorine (both free AND total) that a company or water treatment facility may pump back onto the environment because even in low concentrations, chlorine has the ability to inflict serious harm on an ecosystem.

Testing for Chlorine:

• Liquid Test Kits: Companies such as Taylor, Lamotte and others manufactures test kits which make of use liquid reagents.
• Test Strips: Many companies manufacture test strips which measure chlorine levels as low as 0.05 ppm (see SenSafe Free Chlorine & Total Chlorine) and as high as 5,000 ppm (see Water Check Ultra High II Free Chlorine).

• Chlorine Meters: For people with color blindness or simply the desire NOT to have to interpret color changes on the pads of test strips or in liquid samples, chlorine testing meters take all the guesswork out of testing free & total chlorine levels in water samples. Almost all chlorine testing meters use DPD Reagents in the form of liquids, tablets, powders or reagentstrips.

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 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.

In a previous post we touched upon the topic of drinking water test kits versus pool water test kits. Why do we keep coming back to this topic? Simple: the human body can absorb harmful levels of contaminants through the skin, accidentally through swallowing during a bath or swim, etc.

If what we just said had no validity, why would this phrase exist: “Don’t you go where the Huskies go and don’t you eat that yellow snow!”

Contact with possible sources of contaminants like dog urine mean possible exposure to bacteria and germs which may cause serious, possibly fatal harm to humans. Public swimming pools offer the same level of risk, only without the dog urine — substitute human urine (and more) instead. Need proof? 1 in 5 adults admits peeing in swimming pools

And a desperate cry arises from the masses: “Wait! Chlorine! That kills everything!”

Yes, chlorine has a definite disinfecting a sanitizing effect on water. Hence the reason so many public water systems rely upon it as their primary disinfectant. The USEPA has ruled that a public water supply may not contain more than 4.0 parts per million free chlorine OR total chlorine ( what’s the difference between free and total chlorine? ) for chlorine and yet swimming pools may contain levels FAR in excess of that. Ahem: See bleached hair, bleached swimming suit, bleached skin, etc.

Will the levels of chlorine in a swimming pool harm you? Most likely not in so long as a pool professional or private pool owner properly maintains the water chemical balance. Doing so requires diligent and proper use of Pool & Spa Water Test Kits AND taking corrective action once detecting an imbalance in the water.

Getting back to the differences in typical chlorine levels in pool water comparted to typical chlorine levels in drinking water, though, most people tend not to like or enjoy the taste of pool water when accidentally ingested because of its unpleasant taste and odor. As a general rule, swimming pools tend to have between 1.0 and 3.0 parts per million free/total chlorine ( what’s the difference between free and total chlorine? ) … and as a general rule, most drinking water comes out of the tap at around 0.5 ppm or less — some exceptions will always exist.

For that reason the test kits for pools and spas have much less sensitivity and the color blocks start at higher concentrations than those typically found in drinking water test kits. As an example, the SenSafe Free Chlorine Water Check test strips for drinking water have a low color block of just 0.05 parts per million and several other blocks leading up to 0.5 parts per million, the lowest color block on the Aquacheck 7-Way Test Strips for pool water testing.