Very low CH after fresh fill

AZ_PoolGuy

Member
Jun 29, 2019
5
Mesa, AZ
I just drained and refilled my plaster pool here in AZ, where the water is very hard. My CH is now reading 74 ppm, and recommending I add 73 lbs of Calcium Chloride. Can that be accurate? How can it be so low with such hard tap water?
 
Test your fill water. It should come in at about 150 or more. If it tests there then you're fine. You might have simply tested incorrectly or your reagents are too old. I'm going to do the same here but after the weather cools off. You should really not do this until the daytime temps are below 90. If you had no shell problems then you're lucky. Me, I don't want to risk it.
 
How are you testing CH?

Why do you think Pool Math is recommending 73 lbs (!!) of calcium chloride?

Pool Math is a calculator. It does not make recommendations.
 
How did you get a CH result of 74?
Are you on City of Mesa water?
How old are your reagents?
Clean your testing vials with alcohol.
Rest CH.
Test the pH, TA and CH of your un-softened tap water and report those results here as well.

When doing the TA and CH tests, continue to add drops until the color no longer changes - and then subtract the drop that didn't change the color. And use your SpeedStir as well.

PoolMath is just a calculator - it doesn't provide recommendations.
It will calculate a dosage based on the info you input.
 
How are you testing CH?

Why do you think Pool Math is recommending 73 lbs (!!) of calcium chloride?

Pool Math is a calculator. It does not make recommendations.
I used my FAS-DPD test kit. It registered so low that the sample didn’t even turn red. So I brought a sample to the pool store for a digital test which showed a result of 74 - consistent with my test at home.

And I understand Pool Math is a calculator, but it does make recommendations, as evidenced by the “recommendation” section at the bottom:
 

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How did you get a CH result of 74?
Are you on City of Mesa water?
How old are your reagents?
Clean your testing vials with alcohol.
Rest CH.
Test the pH, TA and CH of your un-softened tap water and report those results here as well.

When doing the TA and CH tests, continue to add drops until the color no longer changes - and then subtract the drop that didn't change the color. And use your SpeedStir as well.

PoolMath is just a calculator - it doesn't provide recommendations.
It will calculate a dosage based on the info you input.
I used my FAS-DPD test kit. It registered so low that the sample didn’t even turn red. So I brought a sample to the pool store for a digital test which showed a result of 74 - consistent with my test at home.

Yes, I’m on Mesa water.

You’re the second person to point out that PoolMath is a calculator, and I understand how calculators work, thank you. However, it literally says “recommendation” as a header for the “recommended” chemical additions, so it does in fact make recommendations.
 
I used my FAS-DPD test kit. It registered so low that the sample didn’t even turn red. So I brought a sample to the pool store for a digital test which showed a result of 74 - consistent with my test at home.

Yes, I’m on Mesa water.

You’re the second person to point out that PoolMath is a calculator, and I understand how calculators work, thank you. However, it literally says “recommendation” as a header for the “recommended” chemical additions, so it does in fact make recommendations.
It makes recommendations based on the target selected- the target is changeable.
Change it to a lower ch level
 
I used my FAS-DPD test kit. It registered so low that the sample didn’t even turn red. So I brought a sample to the pool store for a digital test which showed a result of 74 - consistent with my test at home.

And I understand Pool Math is a calculator, but it does make recommendations, as evidenced by the “recommendation” section at the bottom:
Thank you. It’s not uncommon for people not realize that the “Target” level is to be input manually, and that pool math is not stating that the “Target” is the recommended target for your pool.

Sometimes people may inadvertently change the target accidentally, or they specifically target a number dead center to the “Ideal” level when there is no reason you need to be centered with “Ideal”

This is why the question needs to be asked.

Anyway I’d figure out if your reagents are good and not do anything based on a pool store testing.
 
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You’re the second person to point out that PoolMath is a calculator, and I understand how calculators work, thank you. However, it literally says “recommendation” as a header for the “recommended” chemical additions, so it does in fact make recommendations.

The header states "Recommendation" but then it states, "by weight to reach your target". I can change my CH target to 10,000 and Pool Math will recommend 1,500 lbs of calcium which is obviously crazy. Perhaps Pool Math should change the "Recommendation" header to "Calculation" or "Recommendation to reach your target"
 
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With the new revamp of poolmath there’s been some kinks that they are working on.
Some of which include actually fitting all the information that needs to be displayed in the interface. I really like the “calculation” wording idea.
it’s always been a bit if a contention point with people assuming that’s their exact recommendation magically without adjusting any of the other values.
 
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