Calcium Chloride making TA go all whacky

[internet]

Hot tub is 385 gallon, around 94 degrees (if that matters). Fresh fill on Wednesday readings are the readings for our tap water.

Fresh fill on Wednesday:
- FC:1 pH:7.5 CC: N/A TA: 30 CH: 40 (This is before adding anything)

Added 1oz dichlor and 1.5 oz baking soda the next day:
- FC: 8-10 pH: 8.0 CC: N/a TA: 65 CH: 45.

Added 0.4 oz dry acid to bring pH down. Got it stable at 7.6, and then poured in a bottle of pH Lock.

Thursday night: added 4 oz of Calcium Chloride (Clorox Brand Pool & Spa Calcium Hardness Increaser) - and that's where the weirdness started.

The water became cloudy and the TA shot up to around 180 from 65. pH did not really change at that time, but then was relatively low this morning at 7.2. TA fell to around 110 overnight. There was also some fine white sediment that settled in the tub.

Should I just let it level out, or have I just screwed my water up? It's not the end of the world if I have to drain and refill, but I'm new to this and trying to follow the pool math (on Traditional Spa setting) to figure out the right way to go about this, and this one is baffling me.

Any advice?

 

[boley]

In the following thread, the 2nd post addresses the likely source of your sediment. Leslie's pH Lock

 

[internet]

Ya know, that darn pH Lock was the one thing NOT on my "TFP" list of things to do. But, as expected, I followed the Leslie's store advice. Should have thought twice.

Any word on whether this will self correct over time, or am I looking at refilling from scratch?

 

[pooldv]

Calcium chloride usually takes a day or so to fully dissolve and clear up. I would give it two days and then work on it. And stick to the list!

This one
Pool School - Recommended Pool Chemicals

 

[internet]

Calcium chloride usually takes a day or so to fully dissolve and clear up. I would give it two days and then work on it. And stick to the list!

This one
Pool School - Recommended Pool Chemicals

Well, it looks like a fresh fill for me. Add this one to the Annals of Leslie's Chemicals - pH Lock will absolutely kick your CH readings into total weirdness mode - a.k.a. my CH level went from a little low, to really high with high TA, then down to almost undetectable levels. Going back about a decade to when I was a scientist (after reading about the pH Lock being a phosphate buffer), "weird" really just means "exactly as should be expected". Being a phosphate buffer, and apparently a very effective one, the pH Lock caused not only the Calcium in the added CaCl2 to precipitate out, but also the free calcium in the tap water. Meaning once I kicked the buffer over the limit and activated the precipitation, that was all she wrote for any and all Ca in my water. My guess is the precipitate is now caught up in my filter. So, fresh fill it is.