Calcium Hardness Changed alot in 2 weeks

[richardmb01]

Hello,

My calcium hardness was 140 about 4 weeks ago assuming I performed the test correctly. I have added a few inches of water from my hose since then. We have a well with a water softener. I dis not bypass the softener because I was worried that the straight well water for have metals or something else that would be undesirable.

My current calcium hardness is now 40.

Could this have changed that quickly?

Complete test results

FC 4.5
CC .5
TC 5
PH 7.6
TA 80
CH 40
CYA 60

 

[BoDarville]

Very unlikely that the CH would have changed this much if this was the only water addition since the initial test. Much more likely is that one of the tests was not performed correctly. Here are some Extended Test Kit Directions for testing all water parameters. CH is about halfway down the page.

 

[richardmb01]

I just did the test again 3 times and all were 40. I ran the test the first time 3 times also and it was 140. I am confused of what I could of been doing wrong. With a swg and vinyl liner pool should I adjust this up any or just leave it. Thanks for the help.

 

[linen]

I wouldn't worry about a CH of 40 in a vinyl pool (with the caveat that if you have fiberglass steps, as we have had one report of blistering that may or may not have been caused by low calcium and also a very few reports of metal staining exacerbated on steps due to having low CH, though those should be easily removed by local application of vitC if it does occur).

I am not coming up with a theory as to why your CH changed. Has cya changed?

 

[richardmb01]

I added about a pound of stabilizer a few weeks ago as I am increasing slowly because that test is difficult for me to get consistent results and I am afraid of going too high.