Question on Chlorine loss from Calcium increaser

[MichaelT20]

Hi all. First off want to say hi . Just got my pool installed about a month and a half ago and have been reading up on pool maintenance like crazy. I’ve been following TFP guidance since opening as close as I can. The pools been crystal clear since the first few days.

Just got our salt going too which has been great! I *think* you all can see my pool math history? If not I’ll need to figure out how to let you. I’ve been tracking using pool math since the first few days when my ph was outta control due to the new plaster

Anyway onto my first question. I read in the articles here that adding calcium increaser can sometimes lower FC, even though there’s no chemical explanation for that.

Last night I added about 8lbs and my fc dropped from 4.5 to 0.5. It’s back up to 4 now thanks to some liquid chlorine and cranking the swg a little higher for the day. I added some a few weeks back and had a similar drop at the time.

What’s the theory here? Do you think that the FC reading is thrown off by the calcium increaser and it was really 4.5 even though the dpd read 0.5? Or did the fc really “disappear”.

In other words, is my fc currently 8 not 4 or is it really 4?

P.S. hopefully my signature setup worked but if not I’m using the Taylor K-2006 kit.

P.P.S. The pool builder gave me the nature 2 fusion soft - as per recommended I removed the cartridge and put the empty cap back on after they turned on my swg . They insisted it wouldn’t be a problem but like I said I’m trying to go by this site

 

[Texas Splash]

Welcome to TFP! Sounds like you are doing everything right, and yes, we can see your test logs. As for the potential relationship between calcium and FC, see the discussion below starting at Post #22 where one of our experts @JoyfulNoise does a nice job explaining the issue. Thanks for posting.

(Updated Title) Sudden complete FC loss due calcium chloride

my hypothesis, and i am no chemist the added calcium has created a tiny cloudiness, (calcium precipitation) which has skewed the cya test if you lose fc during the day, but not at night cannot be caused by the calcium, but by UV I should have been clear. Not only the CYA was 60 this morning...

www.troublefreepool.com

 

[MichaelT20]

Awesome thanks . Sounds like it’s still a big unknown. I can only add that I doubt it’s the swg turning off (in my case) as I lost 4ppm
Overnight and that’s never happened before for me.

I added the calcium increaser around 8pm and - not accounting for the chlorine loss - turned off my swg because I didn’t want it running all night. My typical schedule is 8am-8pm so my swg usually doesn’t run at night.

 

[mgtfp]

Thanks for the link to that thread, Pat. Good read.

 

[klanel]

My FC has been consistent lately at 4ppm with the SWG set at 18%. Yesterday, I added 15# of calcium chloride to raise the CH and this morning, the FC was at 2ppm. I ran across this thread while looking to see if the FC could drop rapidly with the addition of Calcium Chloride. And from the few post I've read, although others have experienced the same thing I have, it is discounted as not relative. Since nothing else was changed and with the timing, I am unable to come up with any other possible explanation.

I have bumped my SWG up to 20% and added liquid chlorine and will monitor. At least I am not the only one who seems to have experienced the same.

 

[revitup]

Awesome thanks . Sounds like it’s still a big unknown. I can only add that I doubt it’s the swg turning off (in my case) as I lost 4ppm
Overnight and that’s never happened before for me.

I added the calcium increaser around 8pm and - not accounting for the chlorine loss - turned off my swg because I didn’t want it running all night. My typical schedule is 8am-8pm so my swg usually doesn’t run at night.

Hi all. First off want to say hi . Just got my pool installed about a month and a half ago and have been reading up on pool maintenance like crazy. I’ve been following TFP guidance since opening as close as I can. The pools been crystal clear since the first few days.

Just got our salt going too which has been great! I *think* you all can see my pool math history? If not I’ll need to figure out how to let you. I’ve been tracking using pool math since the first few days when my ph was outta control due to the new plaster

Anyway onto my first question. I read in the articles here that adding calcium increaser can sometimes lower FC, even though there’s no chemical explanation for that.

Last night I added about 8lbs and my fc dropped from 4.5 to 0.5. It’s back up to 4 now thanks to some liquid chlorine and cranking the swg a little higher for the day. I added some a few weeks back and had a similar drop at the time.

What’s the theory here? Do you think that the FC reading is thrown off by the calcium increaser and it was really 4.5 even though the dpd read 0.5? Or did the fc really “disappear”.

In other words, is my fc currently 8 not 4 or is it really 4?

P.S. hopefully my signature setup worked but if not I’m using the Taylor K-2006 kit.

P.P.S. The pool builder gave me the nature 2 fusion soft - as per recommended I removed the cartridge and put the empty cap back on after they turned on my swg . They insisted it wouldn’t be a problem but like I said I’m trying to go by this site

I have experienced the same FC ‘crash’ multiple times when adding calcium chloride.