Pool Calcium Hardness 90 ppm, tap water 150 ppm

[Justice Distributor]

The pool's calcium hardness is 90 ppm.

The hose bib connected to the auto-fill line gives me water with 150 ppm.

How is this possible? Did I let my pH get to high and the water gave up some of it's calcium hardness?

 

[Richard320]

It could be turning to scale.
You could have had a lot of rainwater dilution
The water company switched sources, so the fill water was much lower than it is now.

Now it's time for me to repeat the TFP Mantra: Could you post a full set of test results?

 

[duraleigh]

Rainwater. (please don't tell us you live in Phoenix )

 

[jblizzle]

Rainwater. (please don't tell us you live in Phoenix )

I don't think the tap water would only be 150 if they were in Phoenix :lol:

 

[257WbyMag]

Richard has a good point. Calcium that has precipitated out of solution (as scale on pool surfaces) will not show up on your CH test. He also has another good point in that many municipalities use different water sources at different times of the year. Where I live, my tap water TA and CH vary widely throughout the year.

It would be a good idea to see a full set of tests. I'm curious to know what a CSI might be for your pool.

 

[Justice Distributor]

What I meant by "Did I let my pH get to high and the water gave up some of it's calcium hardness?" was that it might be leaving the water and sticking to the surfaces (scaling).

 

[257WbyMag]

It is certainly plausible.

 

[Melt In The Sun]

The tap water may also come from different sources at different times of the year.