…….. and while I am on this chlorine/chloramine residual rant, below is part of discussion I had with Seachem reps 3 years ago when they decided to dumb down their water treatment directions due to consumers not being able to do math. After discussing this further in private with Dr. Greg Morin, the head chemist & CEO of Seachem, he added more detailed instructions on their FAQ page for Safe.
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Before reading the following please understand that I post this information with the intention to help, not hinder Seachem. I am a very loyal customer of Seachem products, including both Prime & Safe, and have been for many many years. I'm also very well informed when it comes to treating tap water, both chlorine, and chloramine systems.
In Canada, Health Canada has established a maximum acceptable concentration (MAC) for chloramines in drinking water of 3.0 mg/L (3000 µg/L). This MAC is based on a risk evaluation for monochloramine only, as mono-chloramine is usually the predominant chloramine and as information on dichloramine and trichloramine toxicity is insufficient to establish guidelines for these two compounds.
http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/chloramines/index-eng.php
In the USA , the EPA has a standard (the Maximum Residual Disinfectant Level or MRDL) and a health goal (the Maximum Residual Disinfectant Level Goal or MRDLG) for chloramine. The enforceable MRDL is the highest level of a disinfectant allowed in drinking water. The MRDLG is the level of a drinking water disinfectant, below which there is no known or expected risk to health. EPA sets the standard as close to the health goal as feasible, while considering technology, treatment, cost, and risk tradeoffs. In the case for chloramine, the MRDL and MRDLG are the same. (4.0 mg/l or 4.0 ppm)
http://water.epa.gov/drink/contaminants/basicinformation/disinfectants.cfm
American Water Works Association recommends a goal of 2.0 mg/L combined chlorine residual for water leaving the treatment plant and a level of 1.0 mg/L combined chlorine throughout the distribution system.
http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/chloramines/index-eng.php
The average municipal water system maintains residual monochloramine concentrations around 2 mg/L (range: 1.5 mg/L to 2.5 mg/L).
http://www.wqa.org/Portals/0/Technical/Technical Fact Sheets/2014_Chloramine.pdf
3.1 Water
Typical chloramine concentrations of 0.5–2 mg/litre are found in drinking-water supplies where chloramine is used as a primary disinfectant or to provide a chlorine residual in the distribution system (26). Chloramine residuals in the USA range from 0.6 to 5.0 mg/litre; 75% of utilities have finished water with chloramine residual levels between 1.0 and 3.0 mg/litre entering the distribution system.
http://www.who.int/water_sanitation_health/dwq/chemicals/en/monochloramine.pdf
© World Health Organization 2004
Some specific examples of actual chloramine levels found in drinking water located in the USA.
Portland Oregon 2015 Drinking Water Quality Report
Maximum levels of total chlorine residuals from chloramine detected: 2.02 - 2.72 ppm.
http://www.portlandoregon.gov/water/article/244813
San Francisco CA 2013 Water Quality Report
Chloramine residual levels average 2.2 ppm, with a high range of 2.9 ppm.
http://sfwater.org/index.aspx?page=634
San Diego CA 2013 Water Quality Report
Disinfectant Residual (Chloramine) distribution system average 2.2 ppm, with a high range of 4.1.
http://www.sandiego.gov/water/pdf/wq13.pdf
Massachusetts Water Resources Authority 2014 Report
An average of 1.8 ppm chloramine was reported (no maximum level given?)
http://www.mwra.state.ma.us/annual/waterreport/2014results/metro.htm
Houston TX 2013 Water Quality Report
An average of 1.96 ppm chloramine, and a maximum level of 3.8 ppm
http://www.publicworks.houstontx.gov/sites/default/files/images/utilities/wq2013.pdf
Kansas City 2014 Water Quality Report
An average of 2.27 ppm Chloramine, with a maximum level of 3.07 ppm
https://www.kcwaterservices.org/wp-content/uploads/2013/04/2014WQR1.pdf
Miami Florida
An average of chloramine residual in the main system of 2.5, with a high range of 4.2 ppm, and the Aventura (Norwood) system showing an average of 3.1 ppm, with a high range of 4.0 ppm
http://www.miamidade.gov/water/library/reports/water-quality-2014.pdf
Philadelphia
Philly has its tap water sourced from three different water treatment facilities, which across the entire distribution area average out at 1.98 ppm, with a high range of 3.8 ppm.
http://www.phila.gov/water/wu/Water Quality Reports/2014WaterQuality.pdf
Fairfax VA
An annual chloramine residual of 2.8 ppm, with a high of 4.1 ppm.
https://www.fcwa.org/waterqualityreport.pdf
Washington DC
Highest running annual average, 3.0 ppm chloramine, with a high range of 4.2 ppm.
https://www.dcwater.com/news/publications/DC_Water_Annual_WQReport_2014.pdf
So someone please explain to me how treating for 1.0 ppm chloramine is going to be effective for everyone on the planet that uses this product, let alone your customers based in various locations within the USA? The answer is there is no ONE SIZE FITS ALL for these types of questions, one has to have a local water disinfectant base number to start with before they can calculate the quantity of water conditioner such as Seachem Safe required.
There is no possible way on earth that one can make a blanket statement such as "the typical chlorine/chloramine concentrations across many municipalities ", equates to 1.25 mg/l or 1.25 ppm. That's junk science, total nonsense, and you all know it. If you don't know it, spend some time checking out some of the larger municipalities that are using chloramine as their main treatment for disinfection.
I can assure you that what you will find is that most run between 2.0 - 2.5 ppm chloramine. not 1.25 ppm as you are suggesting. Even from a sales perspective it's bad advice, as Seachem is shorting themselves on sales. For chlorine you are probably slightly closer to the mark as chlorine begins to break down the moment that it enters the system. The same does not hold true for chloramine. In other words if the chloramine levels are 2.0-2.5 ppm when leaving the treatment facility, it will retain that strength for many miles while being piped to residential homes. Even homes 50 miles away from the source.
If one is going to go way out on a limb and suggest dosage rates in a "one dose fits all" manner, then as previously suggested it would be far safer to target a level of 2.5 ppm chloramine, or inform consumers to first check with their local water treatment facility.