Testing (Fill/Tap) Water - CH Question

[midlifecrisis]

I tested my fill water a few minutes ago, and for the first time, the tap water. My fill water does not run through my softener or filter. That said, when I tested the fill water, I got a CH of 50, which is about what I suspected, as we have fairly soft water. However, when I test my tap water which goes through my filter and softener, after I put R-0011 solution in the vile, it immediately turned blue.

Question: I have to guess that since Red indicates the presence of calcium, if it turns blue when the R-0011 solution is added, there is a minimum threshold for that solution to detect calcium. If so, what is that threshold? Doesn't impact anything other than a better understanding of the tests I am using.

Here are my Tap results:
Chlorine: 1
PH: 8.04
TA: 160
Calcium: N/A(?)

Fill Water:
PH: 8.03
TA: 160
Calcium: 50

 

[PoolGate]

It is within the test's margin of error. I would consider that almost none and add appropriately for your pool surface (plaster).

 

[proavia]

The result where it turned blue after adding the R-0011 means the CH is zero or very close to it.

We are pimarily interested in the pH, TA and CH of the water you are putting in the pool. That includes the untreated water when you initially fill the pool from empty and the additional water you add do to evaporation, splashout and draining. My initial fill water has a CH of 225ppm to 275ppm and my makeup water (after running thru my water softener) has a CH of 0-50ppm.