Calcium testing with new reagents

ndakotaninja

Well-known member
Nov 26, 2013
90
Elkridge, MD
Hi all,

I opened my pool this year with no issues, balanced things fine, and everything was balanced fine. I was using my reagents I bought last ~August to test things and all levels are in range of what I expected. There was a sale on refill kit a couple weeks ago so I bought a new set of reagents to get some fresh chemicals.

When I tested my levels today, my CH went from 375 with the old chemicals to supposedly 725 with the new chemicals. I'm having 0 issues with the pool, and all other tests came back with the same results as before, accounting slight differences due to chlorine/ph shifts. So the question is, could something actually be wrong? Could the reagents be bad? There is no cloudiness in the pool, no scaling, no issues whatsoever, so I find it hard to believe the CH is actually that high, but I ran the test twice and got the same results both times.

Thoughts?
 

ndakotaninja

Well-known member
Nov 26, 2013
90
Elkridge, MD
I just got them a couple weeks ago (july 4th sale I think?) and they've been inside the A/C house, so shouldn't be an issue there. This is the first time i've used the full set to test since I got it. I tested based on OTPirate's suggestion of wiping the tip off between drops. I tested 4 more times, with slightly differing results.

The first time, it took 21 drops, second time took 20 drops, 3rd time took 18 drops (all much better than the first try this morning which took 31 drops). I tried to be more and more careful each time, also giving 3-5 seconds for the chemicals to mix after each new drop. I noticed if I started just at the 10ml line, it took 1-2 drops fewer than if it was slightly over the 10ml line. So it's possible i was careless this morning and had ~12ml instead of 10, but it's still quite a swing.

Not sure if it's possible for the chemicals to 'settle' since i put them in the carrying case and left it for ~10 days before actually using them. When doing my tests, the liquid inside the bottles was getting shaken around, so maybe that caused better results the more I did them.

I also noticed (and i've seen this before, so maybe this is normal with fresh chemicals) that at around 18 drops, the red would start to form into bubbles, kind of like when you test ph when you're shocking the pool and it can't mix properly and you get bad results. A few drops later with the CH, and the water turned and I was left with almost red sediment. Again, I assume this is all normal, and I feel like I've seen it with the CH tests in the past, but figured i'd mention it in case it wasn't normal.