How accurate is the Hach 5B?

Discussion in 'Water Softener Forum, Questions and Answers' started by BillMN, Mar 16, 2017.

  1. BillMN

    BillMN New Member

    Mar 16, 2017
    I've been planning on replacing my ancient softener and I've been hanging around here for a few months trying to gather information so that I can make an informed decision. Early on, I decided to purchase a Hach 5B to confirm that my old softener wasn't doing the job anymore (it wasn't) and also to check my incoming water. And that's where I encountered a problem.

    I'm on city water and the city publishes an annual water quality report. The latest one states that the water "has approximately 18 grains of hardness". When I tested my water with the Hach 5B, I got 27 grains. Yikes. I went back to the city's report and saw that the city operates a total of 17 wells that draw from 3 different aquifers. Several of the wells are seasonal. I decided to repeat my test every week or two to see if I got any difference in my readings. Unfortunately, it's winter, so I probably didn't get to see what might happen during summer's heavy usage. I did see some variation in my tests - the lowest reading I got was 24 grains and the highest was 29.

    So now I'm confused. Who should I believe? The city presumably has trained technicians with access to lots of expensive lab equipment. And then there's untrained me with a $25 test kit. Does anyone have any ideas as to what might be going on? Obviously there's a big difference between 18 grains and something in the upper 20's. For my typical water consumption (100 to 120 gallons per day), that's probably the difference between 1.0 cu ft and 1.5 cu ft for a softener.
  2. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    Believe the Hach test. Start with 30 grains for your settings. Incidentally, above 30 grains, you want to test 1/2 distilled water and 1/2 test water, and double the reading. You could do that for lower amounts too.

    The 1.5 cuft unit will not use much more space and will not cost much more anyway, unless you were intending to use a cabinet softener. Figure a 9 inch diameter tank for 1 cuft and 10 inches for 1.5 cuft. Plus a 4 inch height difference, but that usually will not matter. Even if you do set it to 20 grains later because the water justifies it, the bigger unit will use a little less salt (1 or 2%) in a year for the same hardness setting. That is a small factor.

    It is possible that your old softener would still work if you set it for 33 grains or so.

    The government person who might be embellishing his product, or your own eyes?:rolleyes:
    Last edited: Mar 16, 2017
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  4. U.S. Filter Pros

    U.S. Filter Pros

    Mar 16, 2017
    Water Filtration
    San Diego, CA
    The Hach 5b test kit is a great kit and highly accurate. We test water hardness for free for our customers here using that same kit. If the city is grabbing water from 17 different wells there can be big differences in the governments testing. If the space you have for a water softener isn't an issue, the price difference between a 1.0 cu. ft. and 1.5 cu. ft. is minimal, on our website it is only a $50 difference between the two. A 1.5 cu. ft. unit will just run more efficiently for you, regenerate less often meaning less wear and tear on the unit and longer life.
  5. Bannerman

    Bannerman Well-Known Member

    Mar 19, 2014
    Ontario, Canada
    The city report maybe an average hardness of all the wells tested. As some wells maybe much harder than others, it is always recommended to test where the softener is to be installed as hardness can vary throughout the distribution system depending on where the wells are located throughout the city.

    Always recommended to program the softener for 2 or 3 additional grains hardness to compensate for hardness variance throughout the day/week/season.
    U.S. Filter Pros likes this.
  6. ditttohead

    ditttohead Water systems designer, R&D

    Jan 9, 2012
    Water systems designer, R&D, Technical Director
    Ontario California
    Correct, the water hardness in the city report is an annual average. Considerable variances are common and expected especially in municipalities that have so many sources.
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