? Relationship Between TDS and Hardness.

Discussion in 'Water Softener Forum, problems, installation and r' started by sidmoore, Aug 11, 2013.

  1. sidmoore

    sidmoore New Member

    Messages:
    8
    Location:
    Comanche, Texas
    Well, I understand that a TDS reading lumps all dissolved solids together and that these, mainly, consist of calcium and magnesium. It is also my understanding that "hardness" is a measure of the amount of calcium (mainly) in the water. What I don't understand is: How can one possibly derive a reasonably close hardness estimate from a TDS reading? Witness my latest conundrum.

    I came to realize that our water softener was no longer softening and decided that I had been pushing its capacity by running scheduled 1100 gallon cycles (this is a Culligan Twin 9100 with a Fleck controller), so, I figured a good first step was to do a few "on-demand" regens and did two for each tank. The practical result so far is the fact that the water now has that "slippery" feeling of softened water when showering. However, my pocket HM Digital TDS meter now reads about a hundred points higher (before: 640).

    So, my main question is: How useful is a TDS meter for measuring water softener performance?'

    Second, if not a TDS meter, what can I, as a homeowner, use to measure hardness?

    Thanx for listening!

    Sid
  2. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,136
    Location:
    Maine
    A TDS meter is pretty much usless for calculating hardness. You need a Hatch 5B kit, about 30 bucks on amazon.
  3. mialynette2003

    mialynette2003 Member

    Messages:
    731
    Location:
    Ocala, Florida
    TDS will in fact be higher on soft water than on hard. As Tom said, a Hach 5B is a very good kit for testing hardness.
  4. sidmoore

    sidmoore New Member

    Messages:
    8
    Location:
    Comanche, Texas
    Thanx for the tip, Tom. I had searched Hach for hardness kits and, for whatever reason, came up only with expensive, or, one shot kits. Much appreciated.

    Sid
  5. sidmoore

    sidmoore New Member

    Messages:
    8
    Location:
    Comanche, Texas
    Mialynette, I had figured that might be true, but, had no way to really know, until you just verified it for me. Thanx!

    Sid
  6. ditttohead

    ditttohead Water systems designer, R&D

    Messages:
    1,828
    Location:
    Ontario California
  7. sidmoore

    sidmoore New Member

    Messages:
    8
    Location:
    Comanche, Texas
Similar Threads: Relationship Between
Forum Title Date
Water Softener Forum, problems, installation and r Newbie: Selecting between the Fleck models Mar 9, 2014
Water Softener Forum, problems, installation and r Time between cycles. Feb 25, 2014
Water Softener Forum, problems, installation and r Price difference between Clack and Fleck Jan 9, 2014
Water Softener Forum, problems, installation and r 750 gallons between regen cycles? Dec 31, 2012
Water Softener Forum, problems, installation and r valve between hose bib supply - softened and untreated Aug 19, 2012

Share This Page