Measuring 30+ grains with Hach 5B kit

Discussion in 'Water Softener Forum, problems, installation and r' started by lifespeed, Jul 28, 2013.

  1. lifespeed

    lifespeed Member

    Messages:
    321
    Location:
    California
    Today I measured 31 grains hardness using Hach 5B in my wildly-varying municipal supply. Is the test kit accurate at these higher hardness levels? I heard mention of diluting the test-tube-sized sample (perhaps with RO water?) and doubling the resulting drop count.

    Is this necessary for accuracy?
  2. Tom Sawyer

    Tom Sawyer In the Trades

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    3,176
    Location:
    Maine
  3. mialynette2003

    mialynette2003 Member

    Messages:
    738
    Location:
    Ocala, Florida
    I've never hears of that. I use a 5B on water that hard and have no problems with it.
  4. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,714
    Location:
    Central Florida
    Hach says "Total hardness test kit with drop count titration covers a 1-30 gpg range with 1 gpg increments." I suggested the dilution technique a while back mainly to (a) comply with Hach's guideline, and (b) save titrating agent. If you're happy counting out 31 drops, experience suggests that's fine, but I'd be a lot happier diluting 3:1 and counting out 10. I've got a source of DI water, though.
  5. ditttohead

    ditttohead Water systems designer, R&D

    Messages:
    1,840
    Location:
    Ontario California
    I have tested the HACH 5B test kit to 80 grains without dilution and found it to be accurate within 2-4%. Not bad considering, but dilution method as mentioned above is preferred.
  6. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,714
    Location:
    Central Florida
    Wow -- that's very good. Speaks well for whoever manufactures their dropper.
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