What about sodium triphosphate in drinking water? Recently, at my place, a sort of filter for hard water was installed. They told me that it contains sodium triphosphate which is dissolved into all the water that enter home, i.e. both cold and hot water to prevent calcium carbonate to accumulate into the plumbing system, dishwasher, etc.... From what I can understand, there is no way this device is considering the flow rate in order to decide how much sodium goes into the water. It just happens.
According to what I googled, sodium triphosphate is used as an additive in many foods and, even though is not considered harmful, high levels may lead to health risks. Also, I have found some links (not in english) stating that such devices should be installed in the hot water plumbings since sodium triphosphate and calcium carbonate interact only at certain temperatures. According to these sources, drinking cold water is not harmful since no chemical reaction took place (but still sodium is present in the water, I believe) and, also, once I use the same cold water for cooking it gets hot and a reaction may take place.
I am quite puzzled and I don't know what to do with this filter. I can move it to hot water only, or I can keep it where it is (both cold and hot) if it's not harmful but I couldn't find any clear information. Is there something that may help?
EDIT 1:
this is the exact product I am using.
EDIT 2:
its chemical formula is Na5 P3 O10
EDIT 3:
this seems to be the device that was installed and this is one of the components that is taking care of the dosing (that is equal to 4-5ppm of sodium triphosphate, apparently)
It appears to be safe, provided that you are putting it into one of the delivery systems that it’s made for which I found through the link you provided.
Here is one of the delivery systems:
https://www.pineco.com/eng/products/dosing/polyphosphate-dosers/spillo-polyphosphates-doser-dm
Per the specs, it delivers 3ppm, which means that you’re only introducing 1ml per 333L of water, which is approximately what the average person uses per day.
Contributing to phosphate load shouldn’t be a concern as someone (with “normal” diet &amp;renal function) has a concentration of 10-300ppm of phosphorus in their urine!
This company also sells water filters for regionally specific water issues like high arsenic, and water softeners with different ion exchange resins based on the ions present in the water. They appear to have a solid understanding of drinking water chemistry, but it’s your domestic water, not mine, so caveat emptor