Calcium Hardness test failure

New2water

LifeTime Supporter
Jun 28, 2011
78
Stockton, CA
I've been working on cleaning and balancing our in-ground pool after 5 weeks of absence. It's clean but not balanced. I added a whole gallon of Muriatic Acid last week and pH is still out of range. Currently it is undergoing Shock treatment and here are the test results:
pH: 8.2+ (don't have a pH meter, just using the daily chlorine & pH test kit.)
TA: 130
CYA: 70
FC:16.5
CC: 1
CH test fails as the sample turns red but then it does not turn blue no matter how many drops of the test chemical I put in. How can I figure it out?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,932
San Dimas, CA (LA County)
If you're using a 25 ml sample and you have a lot of CH buildup, you'll empty the bottle of R-0012 before you finish the test. But how do you know?

Start by making sure the reagent is good. Run the test on your tap water. If you have a softener, get it before the softener. Use 10 ml. 10 drops of R-0010, 3 drops of R-0011. If the color is too faint to see, add a couple more drops. Then start dropping the R-0012 in while you swirl. Each drop will count as 25 CH.

If it doesn't change colors by 10 drops, you got some bad test solution.
If it does change colors, then you got some astronomical CH. You can try testing the pool again using only 10 ml, or try diluting the pool sample 50-50 with distilled water and doubling the results.
 
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New2water

LifeTime Supporter
Jun 28, 2011
78
Stockton, CA
If you're using a 25 ml sample and you have a lot of CH buildup, you'll empty the bottle of R-0012 before you finish the test. But how do you know?

Start by making sure the reagent is good. Run the test on your tap water. If you have a softener, get it before the softener. Use 10 ml. 10 drops of R-0010, 3 drops of R-0011. If the color is too faint to see, add a couple more drops. Then start dropping the R-0012 in while you swirl. Each drop will count as 25 CH.

If it doesn't change colors by 10 drops, you got some bad test solution.
If it does change colors, then you got some astronomical CH. You can try testing the pool again using only 10 ml, or try diluting the pool sample 50-50 with distilled water and doubling the results.
Thank you.
I tested tap water as advised. It took 4 drops of R-0012 in 10 ml of water for it to turn from light pink to light blue. After confirming the reagents are working, I diluted 12 ml of pool water with 12 ml of distilled water and repeated the test. The color turned light blue after 19 drops. With this, the CH is around 380. Is that acceptable or do I need to drain/refill some of the pool water?
Can the Hach Total hardness Test kit Model 5-B (for home water hardness test) be also used to test pool water CH?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,932
San Dimas, CA (LA County)
380 CH is lower than my pool has been in the nine years I've owned it! It's not a big problem to maintain things there. Just keep an eye on the CSI reading.

That still doesn't explain why it wouldn't change colors initially.