Question about adding Calcium Chloride

[MSchutzer]

I have a question concerning how long it takes to register a change in the hardness reading after adding Calcium Chloride. Forty-eight hours ago I added enough Calcium Chloride to raise the hardness level by 40 PPM. Testing today I only see a 10 PPM increase so far.

With all the other chemical additions I make I see the expected change In the testing results within 24 hours, but the Calcium additions seem to take up to week to fully register. I saw the same delayed testing increase the last time I added Calcium months ago.

I wonder if anyone else sees delayed testing results after adding calcium? The water’s cold, 57 degrees, I wonder if that has something to do with it?

For what is worth the pump has had about 10 hours of circulation time over two days since the chemical additions.

 

[mas985]

What is the current CSI level? I would think that Calcium Chloride would dissolve pretty quickly. However, the calcium, might precipitate if CSI is too high.

Also, most folks in Northern Cal have very hard water so I am surprised that you are adding Calcium. Is your fill water mostly surface water or well water? Have you tested the fill water?

 

[MSchutzer]

The CSI level is currently varying between -.3 and -.2 with the PH currently near 8.0. The fill water is Hetch Hetchy surface water and its TA is about 55 ppm and its average Calcium level is 12 ppm, both quite low. This is per the latest water company testing report. I haven't purposely filled the pool significantly in ages. My CH was 310 PPM before we had a bunch of rain which lowered it down to 270 PPM. Added Calcium Chloride to raise the pool back up above 300 ppm.

Your right, the Calcium Chloride seems to look like it completely dissolves within a couple of minutes, it just seems to take a while to completely show up in the testing numbers.

 

[mas985]

The CSI level is currently varying between -.3 and -.2 with the PH currently near 8.0.

Then why raise CH? Is PH stable? I would be very happy with that situation.