Re: So how hard *is* my water?

```You say that for Medium hardness, your Gh test kit reports a hardness of 5?
I am assuming that this is 5 DH.  If so then the kit is correct.  My kit,
Wardley's Hardness, says that 4.48-8.4 DH is regarded as Medium Hardness.

> (This post, and my call to Kent, are because I want a GH of 7 in that tank
> and I am concerned that I have added too much already).
Seems you need to change water and add tap water, if it is hard, to bring
the hardness up.

> So I called Kent, and was told that "Medium hard" means 210 ppm, and that
> 100 ppm is one degree of GH.  They also told me that the hardness test kits
The Kent scale may be different on what range is Low, Meduim and Hard.
But the <100ppm to 1 DH> does not seem right, at least not by my kit.
The conversion is:  1 ppm to 0.056 DH    -or-    1 DH to 17.8 ppm

> typically will not show most of that because they do not measure all of the
> GH contributing chemicals in ROR.
Don't know if this is true, but he might be right, cuz he has no reason
to lie to you right?

> The Kent fellow I spoke to was not able to suggest a reliable test kit, but
> was a big fan of using TDS or conductivity meters.  You may recall I
> recently posted that I had bought one. :)
>
> My meter reports 680 uS on this tank.  Kent says to multiply by .8 for
> numbers in this range to get 544 ppm tds.  Dividing by 200 and multiplying
> by 11
Could you post me a message, explaining how the conductivity can be used
to measure hardness.  I know one person you uses conductivity to measure
nitrate levels. What is TDS?  What is uS? And why all the math to measure
the hardness?

I calculate that I've got a hardness of just under 30 in my soft
> water tank.  I don't even want to *think* about my hard water tank.
Is 30 in DH or ppm?  If it is ppm, then the water is very soft. (would be
an equivalent of 1.68 DH) If it is 30 DH that would mean 534 ppm which is
high in hardness!!!

> How do I get this under control when I can't (apparently) even get a
> measurement on what is there now?  According to the AP test I need to add
> hardness.  According to the KM's interpretation of my conductivity test I'd
> better start doing water changes pronto.
Let's assume that the conductivity test is correct, because it is more
precise.  Then that would mean that your hardness is high which would
coincide with your "several" usage of the RO RIGHT.  I think you should
do the water changes.

Good Luck!!!

Try the Wardley KIT, measures GH and KH and tells you how to convert
between the DH and ppm.
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