Difficulty increasing CH

sportspool

Member
Jun 21, 2019
5
Colleyville, TX
This is my first post but have been a lurker for years... TFP has been such a help over the last 6 years of pool ownership. So thankful for you all...

~20k gallon pool was replastered this past summer. PebbleSheen finish which is great... love it.

Current readings:
FC 3.5
TC 0.0
PH 7.7
TA 70
CH 140
CYA 40

My PH is almost always stable at 7.7. I am only adding chlorine weekly (maybe biweekly now that winter has taken hold) at this point. We do use the spa. Rather than funding MA to drive ph toward 7.4 I’ve resigned myself to letting the pool be where it wants at 7.7. I can get it lower than 7.7 but it seems to want to rise up to 7.7 and wants to stay there. I’ll likely revisit where I let it stay this next season.

Here is my problem since the remodel:
I have not been able to increase my CH. It’s been as low as 120 and have never really seen it higher than 150. I’m not doing any water additions other than rain at this point. I’m having a hard time understanding why I cannot increase my CH despite adding about 75 pound of calcium chloride over the past 5-6 months. I’ve just added 25 pounds of calcium chloride this weekend and the test only indicates a movement from 120 to 140. I’m also using test strips to read the CH in case my test kit isn’t accurate. The test strips indicate the same reading. I obviously have concerns about keeping a low CH level but am unsure how to move an otherwise stubborn pool.

Any advice? Should I not be this concerned? Thanks in advance!
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
27,418
Laughlin, NV
Welcome to the forum.

If you add calcium, it is in the water. Unless you have significant overflow due to water entering the pool that does not have calcium in it (such as rain).

25 pounds of calcium chloride will raise your calcium by 135ppm in the stated size pool.

How old are the reagents you are using to test calcium?
 

sportspool

Member
Jun 21, 2019
5
Colleyville, TX
Thank you. It was a new kit purchased this year, but I suppose I don’t know how old the reagents really are. I was trying to mitigate that risk with the additional testing with the separate strips. Both methods of testing validate the other readings.

I suppose I will have to look at purchasing new reagents and see if there is any change. I just can’t fathom where the CH is going.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
16,517
Northern NJ
What CH product are you using? Where did you buy it? Have you mixed a test solution in a 5 gallon bucket to confirm the chemical is good?
 

sportspool

Member
Jun 21, 2019
5
Colleyville, TX
I am using a Lamotte ColorQ 11 and then generic strips to support those readings.

I have been purchasing Calcium Hardness increase from Leslies. Several purchases over a six month period. Good idea to check product in a bucket. I have not done that but hard to believe they’ve all been bad. It must be something so good idea to try. Thank you.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
44,950
Tallahassee, FL
Let us know what your new tests says please. IF your CH is high you will need to replace some of the water :( Have you been using the Pool Math app or web based Pool Math?

Kim:kim:
 

mguzzy

Gold Supporter
Jul 8, 2015
1,309
OV, CA
Once you get an accurate CH reading you may want to adjust everything in the spring when the rains subside. If you find it to be high let the rains dilute it for you., depending on how much winter rain you get.
 
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kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
44,950
Tallahassee, FL
OUCH! SO glad you found TFP and we were able to point you in the right direction!

Please remember that this draining will also decrease your CYA. Look in my siggy below for recommend levels. I printed it out and have it in my test kit for fast reference.

Kim:kim:
 
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