Adding Calcium Chloride and FC

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ngc4900

ngc4900

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Sep 29, 2012
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The Villages, FL
Pool Size
14600
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
My new three month old pool has been humming trouble free until I added 4 lbs of HTH Calcium increaser (CaCl) and within 48 hrs, my FC plummeted from 9.0 to 1.0. No explanation. I did find the attached info on Pool Math under Calcium hardeness. It makes no sense to me. I was running my FC high so that I could tune my SWG while running my Pump at a low RPM (1600) 24- 7 which others suggested on TFP.

My water is clear, My CC is zero, tonight I will do an OCLT just to be sure, but the only NEW thing I did was add the CaCl. Very frustrated!!!

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Seems to be a common phenomena. Just as you noted, no explanation.

Added Calcium Chloride and FC dropped

Numbers yesterday FC - 3.5 CC - .5 TC - 4.0 PH - 7.6 TA - 60 CH - 220 CYA - 5 or less Bought a 15 lb. bucket of Leslie's Hardness Plus and added 10~12 lbs. last night (plan was to check before adding the rest) Product was "dry broadcast" over the entire pool area, with highest additions at the...
www.troublefreepool.com www.troublefreepool.com
 
It’s a phenomenon we see reported many times when people use calcium chloride products to raise CH. The manufacturers are likely adding anti-caking agents to the mix to reduce the likelihood of their products becoming a solid mass during storage and transportation. Pure calcium chloride is extremely hygroscopic - meaning it absorbs water like crazy. It is the main ingredient in household products like Damp-Rid that people use in storage closets to control moisture. So it’s likely that some of the CH products contain anti-caking agents in them which react with chlorine and reduces chlorine to chloride. As long as those agents are non-toxic and low in concentration, manufacturers don’t have to report them on MSDS forms or they can label them as “proprietary “ or “trade-secret”.

Yes, it’s frustrating but it happens. PoolMath added that warning to make users aware of the potential issues.
 
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thanks everyone for responding. So what is the best Calcium source to prevent this?
 
I don’t know. I still need to add about 100ppm worth of CH.

Now I am a bit worried to do that.

Is Calhypo tablet a thing? If so, then two birds one stone.
 
ngc4900 said:
thanks everyone for responding. So what is the best Calcium source to prevent this?
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There isn’t one. Just monitor your FC if you plan to raise hardness. I’ve added a boatload of calcium chloride and not have any movement in FC and I’ve added and had it drop to zero. It’s somewhat unpredictable so just be diligent.
 

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Lake Placid said:
There isn’t one. Just monitor your FC if you plan to raise hardness. I’ve added a boatload of calcium chloride and not have any movement in FC and I’ve added and had it drop to zero. It’s somewhat unpredictable so just be diligent.
Click to expand...
Same brand of CH increaser?
 
henryforever14 said:
I don’t know. I still need to add about 100ppm worth of CH.

Now I am a bit worried to do that.

Is Calhypo tablet a thing? If so, then two birds one stone.
Click to expand...
Why use tabs? The addition of calcium would be negligible for the rise you are seeking. You’d also need dedicated floaters…you could use granular but again the rise wouldn’t amount to much. Add the calcium and monitor FC.
 
Lake Placid said:
Why use tabs? The addition of calcium would be negligible for the rise you are seeking. You’d also need dedicated floaters…you could use granular but again the rise wouldn’t amount to much. Add the calcium and monitor FC.
Click to expand...
well, I need the FC and I need the CH.

But you are right. After a brief research, looks like Calhypo tablet is too much trouble.
 
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