Salt content of softened water

[Steve B]

Will do some calls tomorrow, Monday, and see where I can get an accurate answer. Will post relevent information for all interested parties. Not sure, but I do drink enough tap water to make it a factor.

Steve

[gfretwell]

Why do you think I wasn't responding to the R/O comment?

R/O DOES remove salt. It does not plug up the membrane because the blocked salt goes out the drain line. Perhaps you should read the book that came with your R/O and you wouldn't be asking us about the salt. BTW they use bigger R/O systems to desalinate sea water so the small amount your water softener puts in is no problem.

[Steve B]

Sorry, now I am really confused. I stated originally I had an RO unit in addition to a softener. You stated I needed to look into getting a RO unit.

Must be too much salt clogging up my brain.

Steve

[Larry Bud]

First of all, don't take medical advice from strangers in a newsgroups. You don't know if you're talking to MDs or 13 year old kids.

2nd, a quick google search found this from the Mayo Clinic:

[Bob]

The salt water from the brine tank is only used to clean the minerals from the resin tank. When that portion of the cycle is complete, a properly operating softener uses clean hard water to back-flush any residual salt down the drain. Thus leaving (at most) a trace of salt. After the regeneration is complete, the only sodium left in the tap water, is that which is normally in the water before it comes into the home.

[hallerb]

that mayo site is excellent and softening water does raise salr content.

if the ware sarts out with 10 grams of hardness, mild hardness, softening adds 80 mg per liter of salt

[Bob]

So where does this salt come from?

[Gary Dyrkacz]

There have a few morsals of wisdom in this thread that are the key to understanding the exchange softner:

David Martel wrote: " Sounds like you have an ion exchange resin type water softener. In these there is a resin which releases sodium and takes up calcium. So the amount of sodium (which is the "salt" that concerns you) in your tap water is a function of the hardness of your well water. Really hard water will yield somewhat more "salty" tap water than slightly hard water does. For most folks this "saltiness" is thought to be insignificant. By having the hardness of your well water tested and reading the owners manual or writing to the manufacturer you should be able to figure out how much salt is in your water. Then figure out how much water you drink per day and you'll know how much salt is being added to your diet by your water. Run this number by your physician for his advise." Dave M.

Another critical piece of info was:

"Did he tell you to cut down on *table* salt (sodium chloride) or sodium? What's left after the softener does its thing is sodium carbonate, not sodium chloride." dadiOH

Bob had two pieces of useful info: "There's twice as much sodium in the water as the calcium, magnesium, and iron that was in the the hard water. (it's not much) The kitchen cold water faucet and the outside faucets are probably plumbed with hard water rather than softened water." and "The salt water from the brine tank is only used to clean the minerals fromthe resin tank. When that portion of the cycle is complete, a properlyoperating softener uses clean hard water to back-flush any residual salt down the drain. Thus leaving (at most) a trace of salt. After the regeneration is complete, the only sodium left in the tap water, is that which is normally in the water before it comes into the home." Bob

You put all this together and you have pretty much the correct story on the softner side. As for the R/O it is not clear how the OP's system is really set up. Yes, in prinicple it should remove substantial amounts of Ca, Mg, and Fe itself.

Gary Dyrkacz [e-mail] Radio Control Aircraft/Paintball Physics/Paintball for 40+

[Cue]

Water softeners and a low sodium diet

Maintaining a low-sodium diet is more difficult if you use some types of "softened water."

To understand the problem you need to know a little about how water softeners work. They usually contain a chamber filled with beads or a chemical matrix called zeolite. This is an ion-exchanger and acts by replacing the chemicals in the water that make it hard (calcium and magnesium) with another ion, usually sodium. When the beads are "full" of calcium and magnesium, they are regnerated by passing a high level of sodium chloride through the exchanger, which displaces the calcium and magnesium and replaces it with sodium. Now, when the beads are exposed to hard water again, they continue to do their job of swapping calcium and magnesium for sodium.

For most individuals, the amount of sodium present in softened water is not a health problem. If however, you are trying to maintain a low sodium diet, this can add to your difficulties.

The amount of sodium in softened water can vary. According to a paper by Yarows et al., (Sodium concentration from water softeners, Arch Intern Med. 1997 Jan 27;157(2):218-22) the sodium concentration of softened well water averaged 278 mg/L but the variation was very large. Levels from 46 to 1219 mg/L were observed. 17% of households had sodium levels above 400 mg/L. The amount of sodium that gets added depends on how hard the water is to start with. If the water is very hard then the sodium level will be higher, as shown in the table below.

Initial Hardness Na added (Grains CaCO3/gallon) mg/liter

10 75 20 150 30 225

The above figures are the amount that is in addition to the sodium content before the water is softened. If you are trying to limit your sodium intake to 1500 mg/day, then drinking 2 liters of water with 400 mg/L sodium over the course of a day will represent more than half your daily limit! In the same study, the mean sodium concentration of municipal, non-softened water was 110 mg/L (range 0 - 253 mg/L).

There are types of water softeners that do not add sodium to the water. Alternatively, if the ion-exchanger type of water softener is regenerated using potassium chloride, instead of sodium chloride, then potassium would be added to the water instead of sodium as the water was softened. However, in some patients with renal or cardiac disease, diabetes or high blood pressure, there can also be complications due to increased potassium intake so this should only be performed in consultation with your physician.

[Adiabatic]

Yes, this needed to be said. High potassium levels can be very bad. K+ and Na+ regulate muscle contraction and relaxation. This includes cardiac muscle.