My softener (Whirlpool 30K) is about 7 years old. When it was installed, and until recently, the incoming hardness was around 25 grains per gallon (GPG).

Probably due to new city water sources/methods, I noticed the incoming hardness has decreased to around 12 GPG/200 PPM. In response, I started to lower the water softener's setting for incoming hardness level (in GPG increments) to get it to the right new level. Knowing nothing is perfect, my approach was to start low and work my way up until I saw the first hint of hardness. Testing of input and output hardness is done with a reliable Hach 5-EP test kit, not strips or anything like that.

The issue is I am seeing no hardness at even with the softener set to 1 GPG. My assumption was that if incoming is ~12 GPG, and water softener is set to ~1 GPG, the output should be ~11 GPG, and so forth.

Is my assumption correct? How exactly does the GPG setting on the water softener work? What exactly does it control?

Just wondering if I have a bad water softener. Any help appreciated.


1 Answer 1


How long are you waiting between tests? That's not how it works, anyway.

The hardness setting on the softener relates to how often (time, or in more modern units, volume of water used) it regenerates the resin, removing collected hardness ions and replacing them with sodium ions. Changing that setting when the resin is not exhausted makes no difference to the output, until the next regeneration cycle, or the need for one that doesn't happen due to the changed setting.

Each time the resin is regenerated, the hardness will be zero until the resin is exhausted. Since you know the incoming hardness, just set it at that hardness, rather than whatever you are trying to achieve by undershooting and adjusting.

What will happen, over a long enough time, is that your hardness will go from 0 to 12 at some point after the resin is regenerated, and before it's regenerated again, if you are not regenerating often enough. Presumably that would be a bit less than 10% of the time or volume between cycles with a setting of 1 and incoming water at 12, so you'd have days and days of hard water, and soft water less than 10% of the time - but if you check when you change it, you'll see no difference. If you regenerate too often, you'll waste water and salt.

So if you want to fiddle with the adjustments, you'll have to keep track of when your softener regenerates, and be checking the water the day (ideally evening, since they typical go at 2-3 AM) before that happens, to see if it's still soft or not at that point. That will not be aided by massively under-setting (other than you might have a whole week of hard water before a regeneration.)

The more-modern units go at 2-3AM (or whenever set) after using their defined amount of water. They may also default to something like "every 2 weeks even if not enough water used" as a backup for a failed volume sensor.

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